10-Q

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

(Mark One)

þ	QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the quarterly period ended September 30, 2018

or

o	TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the transition period from to

Commission File Number: 001-14989

WESCO International, Inc.

(Exact name of registrant as specified in its charter)

Delaware (State or other jurisdiction of incorporation or organization)	25-1723342 (I.R.S. Employer Identification No.)
225 West Station Square Drive Suite 700 Pittsburgh, Pennsylvania (Address of principal executive offices)	15219 (Zip Code)

(412) 454-2200

(Registrant's telephone number, including area code)

Not applicable.

(Former name, former address and former fiscal year, if changed since last report) 

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for at least the past 90 days.              Yes þ No o

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). Yes þ No o

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-2 of the Exchange Act.

Large accelerated filer þ	Accelerated filer o
Non-accelerated filer o	Smaller reporting company o
	Emerging growth company o
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes o No þ

As of November 1, 2018, 46,691,008 shares of common stock, $0.01 par value, of the registrant were outstanding.

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

QUARTERLY REPORT ON FORM 10-Q

Table of Contents

	Page
PART I—FINANCIAL INFORMATION
Item 1. Financial Statements.	2
Item 2. Management's Discussion and Analysis of Financial Condition and Results of Operations.	22
Item 3. Quantitative and Qualitative Disclosures About Market Risk.	29
Item 4. Controls and Procedures.	29
PART II—OTHER INFORMATION
Item 1. Legal Proceedings.	30
Item 1A. Risk Factors.	30
Item 2. Unregistered Sales of Equity Securities and Use of Proceeds.	30
Item 6. Exhibits.	31
Signatures	32

1

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

PART I—FINANCIAL INFORMATION

Item 1. Financial Statements.

The interim financial information required by this item is set forth in the unaudited Condensed Consolidated Financial Statements and Notes thereto in this Quarterly Report on Form 10-Q, as follows:

	Page
Condensed Consolidated Balance Sheets (unaudited)	3
Condensed Consolidated Statements of Income and Comprehensive Income (unaudited)	4
Condensed Consolidated Statements of Cash Flows (unaudited)	5
Notes to Condensed Consolidated Financial Statements (unaudited)	6

2

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATED BALANCE SHEETS

(In thousands of dollars, except share data)

(unaudited)

	As of
	September 30, 2018			December 31, 2017
Assets
Current assets:
Cash and cash equivalents	$	142,760		$	117,953
Trade accounts receivable, net of allowance for doubtful accounts of $25,272 and $21,313 in 2018 and 2017, respectively	1,265,880			1,170,080
Other accounts receivable	80,676			101,229
Inventories	926,768			956,148
Prepaid expenses and other current assets	90,415			63,439
Total current assets	2,506,499			2,408,849
Property, buildings and equipment, net of accumulated depreciation of $289,273 and $278,455 in 2018 and 2017, respectively	157,129			156,445
Intangible assets, net of accumulated amortization of $248,797 and $223,554 in 2018 and 2017, respectively	334,026			367,104
Goodwill	1,755,292			1,771,877
Other assets	25,845			31,193
Total assets	$	4,778,791		$	4,735,468
Liabilities and Stockholders’ Equity
Current liabilities:
Accounts payable	$	813,395		$	799,520
Accrued payroll and benefit costs	73,074			72,686
Short-term debt	31,125			34,075
Current portion of long-term debt	1,179			1,224
Bank overdrafts	30,266			37,644
Other current liabilities	102,489			95,820
Total current liabilities	1,051,528			1,040,969
Long-term debt, net of debt discount and debt issuance costs of $10,596 and $14,224 in 2018 and 2017, respectively	1,229,314			1,313,261
Deferred income taxes	147,048			136,858
Other noncurrent liabilities	119,064			128,237
Total liabilities	$	2,546,954		$	2,619,325
Commitments and contingencies (Note 10)
Stockholders’ equity:
Preferred stock, $.01 par value; 20,000,000 shares authorized, no shares issued or outstanding	—			—
Common stock, $.01 par value; 210,000,000 shares authorized, 59,152,810 and 59,045,762 shares issued and 46,753,475 and 47,009,540 shares outstanding in 2018 and 2017, respectively	592			591
Class B nonvoting convertible common stock, $.01 par value; 20,000,000 shares authorized, 4,339,431 issued and no shares outstanding in 2018 and 2017, respectively	43			43
Additional capital	1,006,222			999,156
Retained earnings	2,249,327			2,079,697
Treasury stock, at cost; 16,738,766 and 16,375,653 shares in 2018 and 2017, respectively	(669,212		)	(647,158		)
Accumulated other comprehensive loss	(349,619		)	(312,590		)
Total WESCO International, Inc. stockholders' equity	2,237,353			2,119,739
Noncontrolling interests	(5,516		)	(3,596		)
Total stockholders’ equity	2,231,837			2,116,143
Total liabilities and stockholders’ equity	$	4,778,791		$	4,735,468

The accompanying notes are an integral part of the condensed consolidated financial statements.

3

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME

(In thousands of dollars, except per share data)

(unaudited)

	Three Months Ended						Nine Months Ended
	September 30						September 30
	2018			2017			2018			2017
Net sales (Note 3)	$	2,067,245		$	2,000,159		$	6,165,154		$	5,682,375
Cost of goods sold (excluding depreciation and
amortization)	1,670,037			1,614,814			4,988,103			4,580,896
Selling, general and administrative expenses (Note 8)	284,073			280,497			867,790			815,653
Depreciation and amortization	15,618			16,074			47,321			47,758
Income from operations	97,517			88,774			261,940			238,068
Net interest and other (Notes 8 and 9)	17,050			16,835			54,574			49,469
Income before income taxes	80,467			71,939			207,366			188,599
Provision for income taxes	13,822			18,363			40,077			47,684
Net income	66,645			53,576			167,289			140,915
Less: Net loss attributable to noncontrolling interests	(204		)	(99		)	(1,921		)	(3		)
Net income attributable to WESCO International, Inc.	$	66,849		$	53,675		$	169,210		$	140,918
Other comprehensive income (loss):
Foreign currency translation adjustments	20,486			51,148			(37,029		)	96,097
Post retirement benefit plan adjustments, net of tax	—			—			—			252
Comprehensive income attributable to WESCO International, Inc.	$	87,335		$	104,823		$	132,181		$	237,267
Earnings per share attributable to WESCO International, Inc.
Basic	$	1.42		$	1.13		$	3.60		$	2.93
Diluted	$	1.41		$	1.12		$	3.56		$	2.90

The accompanying notes are an integral part of the condensed consolidated financial statements.

4

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(In thousands of dollars)

(unaudited)

	Nine Months Ended
	September 30
	2018			2017
Operating activities:
Net income	$	167,289		$	140,915
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	47,321			47,758
Deferred income taxes	12,194			8,433
Other operating activities, net	7,590			12,617
Changes in assets and liabilities:
Trade accounts receivable, net	(104,215		)	(174,667		)
Other accounts receivable	19,859			4,421
Inventories	23,189			(86,736		)
Prepaid expenses and other assets	(22,088		)	(8,515		)
Accounts payable	18,235			138,348
Accrued payroll and benefit costs	2,788			2,383
Other current and noncurrent liabilities	2,298			(3,846		)
Net cash provided by operating activities	174,460			81,111
Investing activities:
Capital expenditures	(23,749		)	(15,970		)
Other investing activities	3,609			3,490
Net cash used in investing activities	(20,140		)	(12,480		)
Financing activities:
Proceeds from issuance of short-term debt	116,775			130,890
Repayments of short-term debt	(119,239		)	(114,972		)
Proceeds from issuance of long-term debt	994,323			1,079,718
Repayments of long-term debt	(1,081,323		)	(1,076,718		)
Repurchases of common stock (Note 7)	(27,055		)	(106,702		)
Other financing activities, net	(8,301		)	(4,380		)
Net cash used in financing activities	(124,820		)	(92,164		)
Effect of exchange rate changes on cash and cash equivalents	(4,693		)	7,485
Net change in cash and cash equivalents	24,807			(16,048		)
Cash and cash equivalents at the beginning of period	117,953			110,131
Cash and cash equivalents at the end of period	$	142,760		$	94,083
Supplemental disclosures:
Cash paid for interest	$	37,138		$	35,344
Cash paid for income taxes	48,744			50,909

The accompanying notes are an integral part of the condensed consolidated financial statements.

5

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS

(unaudited)

1. ORGANIZATION

WESCO International, Inc. ("WESCO International") and its subsidiaries (collectively, “WESCO” or the "Company"), headquartered in Pittsburgh, Pennsylvania, is a full-line distributor of electrical, industrial and communications maintenance, repair and operating ("MRO") and original equipment manufacturer ("OEM") products, construction materials, and advanced supply chain management and logistics services used primarily in the industrial, construction, utility and commercial, institutional and government markets. WESCO serves approximately 70,000 active customers globally through approximately 500 branches and 10 distribution centers located primarily in the United States and Canada, with operations in 16 additional countries.

2. ACCOUNTING POLICIES

Basis of Presentation

The accompanying unaudited Condensed Consolidated Financial Statements of WESCO have been prepared in accordance with Rule 10-01 of Regulation S-X of the Securities and Exchange Commission (the “SEC”). The unaudited condensed consolidated financial information should be read in conjunction with the audited Consolidated Financial Statements and Notes thereto included in WESCO’s 2017 Annual Report on Form 10-K as filed with the SEC on February 22, 2018. The Condensed Consolidated Balance Sheet at December 31, 2017 was derived from the audited Consolidated Financial Statements as of that date, but does not include all of the disclosures required by accounting principles generally accepted in the United States of America.

The unaudited Condensed Consolidated Balance Sheet as of September 30, 2018, the unaudited Condensed Consolidated Statements of Income and Comprehensive Income for the nine months ended September 30, 2018 and 2017, respectively, and the unaudited Condensed Consolidated Statements of Cash Flows for the nine months ended September 30, 2018 and 2017, respectively, in the opinion of management, have been prepared on the same basis as the audited Consolidated Financial Statements and include all adjustments necessary for the fair statement of the results of the interim periods presented herein. All adjustments reflected in the unaudited condensed consolidated financial information are of a normal recurring nature unless indicated. The results for the interim periods presented herein are not necessarily indicative of the results to be expected for the full year.

Reclassifications

Effective January 1, 2018, WESCO adopted Accounting Standards Update (ASU) 2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The adoption of this ASU, as described below and in Note 8, resulted in the reclassification of amounts reported in the unaudited Condensed Consolidated Statements of Income and Comprehensive Income for the three and nine months ended September 30, 2017.

Recently Adopted Accounting Pronouncements

Effective January 1, 2018, WESCO adopted ASU 2014-09, Revenue from Contracts with Customers, and all the related amendments (“Topic 606”) using the modified retrospective approach to all open contracts. There was no impact to WESCO’s previously reported consolidated financial statements and WESCO does not expect the adoption of Topic 606 to have a material impact on its revenue and results of operations on an ongoing basis.

WESCO’s significant accounting policies are disclosed in Note 2 of the Notes to Consolidated Financial Statements in the Annual Report on Form 10-K for the year ended December 31, 2017. Changes to the Company’s significant accounting policies as a result of adopting Topic 606 are described in Note 3 below.

In August 2016, the Financial Accounting Standards Board (FASB) issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force). This ASU provides guidance on eight specific cash flow issues where there is diversity in practice. The Company adopted this ASU in the first quarter of 2018. The adoption of this guidance did not have an impact on the unaudited condensed consolidated financial information presented herein.

In March 2017, the FASB issued ASU 2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. This ASU requires that an employer disaggregate the service cost from the other components of net benefit cost. The Company adopted this guidance on a retrospective basis in the first quarter of 2018. See Note 8 for a description of the impact of this accounting standard on the unaudited Condensed Consolidated Statements of Income and Comprehensive Income presented herein. The adoption of this guidance did not have an impact on the Company's unaudited Condensed Consolidated Balance Sheets and the unaudited Condensed Consolidated Statements of Cash Flows presented herein.

6

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS—(CONTINUED)

(unaudited)

In May 2017, the FASB issued ASU 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting. This ASU clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions, or the classification of the award (as equity or liability) changes as a result of the change in terms or conditions. The Company adopted this ASU in the first quarter of 2018. The adoption of this guidance did not have an impact on the unaudited condensed consolidated financial information presented herein.

Recently Issued Accounting Pronouncements

In February 2016, the FASB issued ASU 2016-02, Leases, a comprehensive new standard that amends various aspects of existing accounting guidance for leases, including the recognition of a right-of-use asset and a lease liability in the balance sheet and disclosing key information about leasing arrangements. This ASU is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. During 2018, the FASB issued additional ASUs that address implementation issues and correct or improve certain aspects of the new accounting guidance for leases, including ASU 2018-10, Codification Improvements to Topic 842, Leases and ASU 2018-11, Leases (Topic 842): Targeted Improvements. These ASUs do not change the core principles in the leasing standard outlined above. The amendments in ASU 2018-11 provide an optional transition method that allows entities to initially apply the new leases standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. Consequently, an entity’s reporting for the comparative periods will continue to be in accordance with current lease accounting guidance. Management established a cross-functional team to evaluate and implement the new standard. The team selected a third-party software solution to facilitate the accounting and financial reporting requirements of the new lease standard. Lease data elements have been gathered and are currently being migrated to the software solution. The new standard will be adopted in the first quarter of 2019 and the Company expects to use the optional transition method. While the Company has not yet completed its evaluation of the effects of adopting this ASU, right-of-use assets and lease liabilities will be recorded in the Consolidated Balance Sheets as of the effective date and thereafter.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which introduces new guidance for the accounting for credit losses on certain financial instruments. The amendments in this ASU are effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted. Management does not expect the adoption of this accounting standard to have a material impact on its consolidated financial statements and notes thereto.

In January 2017, the FASB issued ASU 2017-04, Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment, which eliminates Step 2 of the goodwill impairment test. Under the amendments in this ASU, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. An entity should apply the amendments in this ASU on a prospective basis. This guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Management expects to adopt this ASU in the fourth quarter of 2018 when the Company performs its annual impairment testing. The Company does not expect the adoption of this accounting standard to have a material impact on its consolidated financial statements and notes thereto.

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement, which amends the disclosure requirements for recurring and nonrecurring fair value measurements by removing, modifying and adding certain disclosures. The amendments in this ASU are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted. Management does not expect the adoption of this accounting standard to have a material impact on its consolidated financial statements and notes thereto.

In August 2018, the FASB issued ASU 2018-14, Compensation—Retirement Benefits—Defined Benefit Plans—General (Subtopic 715-20): Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans, which amends the disclosure requirements for all employers that sponsor defined benefit pension and other post retirement plans by removing and adding certain disclosures. The amendments in this ASU are effective for fiscal years ending after December 15, 2020. Early adoption is permitted. Management does not expect the adoption of this accounting standard to have a material impact on its consolidated financial statements and notes thereto.

Other pronouncements issued by the FASB or other authoritative accounting standards groups with future effective dates are either not applicable or are not expected to be significant to WESCO’s financial position, results of operations or cash flows.

7

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS—(CONTINUED)

(unaudited)

3. REVENUE

WESCO’s revenue arrangements generally consist of single performance obligations to transfer a promised good or service, or a combination of goods and services. Revenue is recognized when control has transferred to the customer, which is generally when the product has shipped from a WESCO facility or directly from a supplier. For products that ship directly from suppliers to customers, WESCO acts as the principal in the transaction and recognizes revenue on a gross basis. Revenue for integrated supply services is recognized over time based on hours incurred. This method reflects the transfer of control as the customer benefits from these services as they are being performed. WESCO generally satisfies its performance obligations within a year or less.

WESCO generally does not have significant financing terms associated with its contracts; payments are normally received within 60 days. There are no significant costs associated with obtaining customer contracts. WESCO generally passes through the warranties offered by the applicable manufacturer or supplier to its customers. Sales taxes (and value added taxes in foreign jurisdictions) collected from customers and remitted to governmental authorities are excluded from net sales.

The following tables disaggregate WESCO’s revenue by end market and geography:

	Three Months Ended				Nine Months Ended
	September 30				September 30
(In thousands)	2018		2017		2018		2017
Industrial	$	723,869	$	722,227	$	2,243,590	$	2,111,813
Construction	686,165		674,996		2,007,708		1,870,406
Utility	345,937		312,501		998,438		861,162
Commercial, Institutional and Government ("CIG")	311,274		290,435		915,418		838,994
Total by end market	$	2,067,245	$	2,000,159	$	6,165,154	$	5,682,375

	Three Months Ended				Nine Months Ended
	September 30				September 30
(In thousands)	2018		2017		2018		2017
United States	$	1,525,393	$	1,473,016	$	4,571,533	$	4,267,684
Other (1)	541,852		527,143		1,593,621		1,414,691
Total by geography	$	2,067,245	$	2,000,159	$	6,165,154	$	5,682,375

⁽¹⁾  Other primarily includes net sales originating in Canada.

WESCO distributes products and provides services to customers globally within the following end markets: (1) industrial, (2) construction, (3) utility, and (4) CIG. Revenue is measured as the amount of consideration WESCO expects to receive in exchange for transferring goods or providing services.

In accordance with certain contractual arrangements, WESCO receives payment from its customers in advance and recognizes such payment as deferred revenue. Revenue for advance payment is recognized when the performance obligation has been satisfied and control has transferred to the customer, which is generally upon shipment. Deferred revenue is usually recognized within a year or less from the date of the customer’s advance payment. At September 30, 2018 and December 31, 2017, $8.8 million and $15.5 million, respectively, of deferred revenue was recorded as a component of other current liabilities in the Condensed Consolidated Balance Sheets.

WESCO’s revenues are adjusted for variable consideration, which includes customer volume rebates, returns, and discounts. WESCO measures variable consideration by estimating expected outcomes using analysis and inputs based upon anticipated performance, historical data, as well as current and forecasted information. Measurement and recognition of variable consideration is reviewed by management on a monthly basis and revenue is adjusted accordingly. Variable consideration reduced revenue for the three months ended September 30, 2018 and 2017 by approximately $25.1 million and $24.2 million, respectively, and by approximately $74.5 million and $66.5 million for the nine months ended September 30, 2018 and 2017, respectively.

Shipping and handling costs are recognized in net sales when they are billed to the customer. These costs are recognized as a component of selling, general and administrative expenses when WESCO does not bill the customer. WESCO has elected to recognize shipping and handling costs as a fulfillment cost. Shipping and handling costs recorded as a component of selling, general

8

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS—(CONTINUED)

(unaudited)

and administrative expenses totaled $18.8 million and $15.5 million for the three months ended September 30, 2018 and 2017, respectively, and $55.6 million and $43.2 million for the nine months ended September 30, 2018 and 2017, respectively.

4. FAIR VALUE OF FINANCIAL INSTRUMENTS

The Company’s financial instruments consist of cash and cash equivalents, accounts receivable, accounts payable, bank overdrafts, and outstanding indebtedness. The reported carrying amounts of WESCO's financial instruments approximated their fair values as of September 30, 2018 and December 31, 2017.

The Company uses a market approach to determine the fair value of its debt instruments, utilizing quoted prices in active markets, interest rates and other relevant information generated by market transactions involving similar instruments. Therefore, the Company's debt instruments are classified as Level 2 within the fair value hierarchy.

5. GOODWILL

The following table sets forth the changes in the carrying value of goodwill:

	Nine Months Ended
	September 30
(In thousands)	2018
Beginning balance January 1	$	1,771,877
Foreign currency exchange rate changes	(16,585		)
Ending balance September 30	$	1,755,292

6. STOCK-BASED COMPENSATION

WESCO’s stock-based employee compensation plans are comprised of stock-settled stock appreciation rights, restricted stock units and performance-based awards. Compensation cost for all stock-based awards is measured at fair value on the date of grant and compensation cost is recognized, net of estimated forfeitures, over the service period for awards expected to vest. The fair value of stock-settled stock appreciation rights and performance-based awards with market conditions is determined using the Black-Scholes and Monte Carlo simulation models, respectively. The fair value of restricted stock units and performance-based awards with performance conditions is determined by the grant-date closing price of WESCO’s common stock. The forfeiture assumption is based on WESCO’s historical employee behavior that is reviewed on an annual basis. No dividends are assumed.

Effective January 1, 2018, performance-based awards are based on two equally-weighted performance measures, which include the three-year average growth rate of the Company’s fully diluted earnings per share and the three-year cumulative return on net assets. From 2015 to 2017, the two equally-weighted performance-based award metrics were the three-year average growth rate of WESCO's net income and WESCO's total stockholder return in relation to the total stockholder return of a select group of peer companies over a three-year period.

During the three and nine months ended September 30, 2018 and 2017, WESCO granted the following stock-settled stock appreciation rights, restricted stock units and performance-based awards at the following weighted-average fair values:

	Three Months Ended				Nine Months Ended
	September 30, 2018		September 30, 2017		September 30, 2018		September 30, 2017
Stock-settled stock appreciation rights granted	9,415		12,076		509,046		455,807
Weighted-average fair value	$	17.40	$	15.74	$	18.38	$	20.52
Restricted stock units granted	2,686		2,313		119,457		100,993
Weighted-average fair value	$	61.41	$	57.30	$	62.72	$	71.33
Performance-based awards granted	—		—		44,144		39,978
Weighted-average fair value	$	—	$	—	$	62.80	$	76.63

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WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS—(CONTINUED)

(unaudited)

The fair value of stock-settled stock appreciation rights was estimated using the following weighted-average assumptions:

	Three Months Ended				Nine Months Ended
	September 30, 2018		September 30, 2017		September 30, 2018		September 30, 2017
Risk free interest rate	2.8	%	1.8	%	2.5	%	1.9	%
Expected life (in years)	5		5		5		5
Expected volatility	28	%	28	%	28	%	29	%

The risk-free interest rate is based on the U.S. Treasury Daily Yield Curve as of the grant date. The expected life is based on historical exercise experience and the expected volatility is based on the volatility of the Company's daily stock prices over a five-year period preceding the grant date.

The following table sets forth a summary of stock-settled stock appreciation rights and related information for the nine months ended September 30, 2018:

	Awards		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (In years)	Aggregate Intrinsic Value (In thousands)
Outstanding at December 31, 2017	2,238,607		$	57.75
Granted	509,046		62.68
Exercised	(186,662	)	40.73
Forfeited	(168,824	)	69.12
Outstanding at September 30, 2018	2,392,167		59.32		6.3	$	16,779
Exercisable at September 30, 2018	1,476,763		$	58.03	4.9	$	13,566

The following table sets forth a summary of time-based restricted stock units and related information for the nine months ended September 30, 2018:

	Awards		Weighted- Average Fair Value
Unvested at December 31, 2017	290,054		$	58.11
Granted	119,457		62.72
Vested	(59,905	)	68.78
Forfeited	(14,539	)	57.09
Unvested at September 30, 2018	335,067		$	57.89

10

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS—(CONTINUED)

(unaudited)

Performance shares are awards for which the vesting will occur based on market or performance conditions. The following table sets forth a summary of performance-based awards for the nine months ended September 30, 2018:

	Awards		Weighted- Average Fair Value
Unvested at December 31, 2017	148,508		$	60.23
Granted	44,144		62.80
Vested	—		—
Forfeited	(52,342	)	65.15
Unvested at September 30, 2018	140,310		$	59.20

The fair value of the performance shares granted during the nine months ended September 30, 2018 and 2017 was estimated using the following weighted-average assumptions:

	Nine Months Ended
	September 30, 2018		September 30, 2017
Grant date share price	$	62.80	$	71.65
WESCO expected volatility	n/a		29		%
Peer group median volatility	n/a		24		%
Risk-free interest rate	n/a		1.5		%
Correlation of peer company returns	n/a		114		%

The unvested performance-based awards in the table above include 48,805 shares in which vesting of the ultimate number of shares is dependent upon WESCO's total stockholder return in relation to the total stockholder return of a select group of peer companies over a three-year period. These awards are accounted for as awards with market conditions; compensation cost is recognized over the service period, regardless of whether the market conditions are achieved and the awards ultimately vest.

Vesting of the remaining 91,505 shares of performance-based awards in the table above is dependent upon the achievement of certain performance targets, including 48,805 that are dependent upon the three-year average growth rate of WESCO's net income, 21,350 that are dependent upon the three-year average growth rate of the Company's fully diluted earnings per share, and 21,350 that are based upon the three-year cumulative return on net assets. These awards are accounted for as awards with performance conditions; compensation cost is recognized over the performance period based upon WESCO's determination of whether it is probable that the performance targets will be achieved.

WESCO recognized $4.1 million and $3.5 million of non-cash stock-based compensation expense, which is included in selling, general and administrative expenses, for the three months ended September 30, 2018 and 2017, respectively. WESCO recognized $12.1 million and $11.3 million of non-cash stock-based compensation expense, which is included in selling, general and administrative expenses, for the nine months ended September 30, 2018 and 2017, respectively. As of September 30, 2018, there was $22.9 million of total unrecognized compensation cost related to non-vested stock-based compensation arrangements for all awards previously made, of which approximately $4.1 million is expected to be recognized over the remainder of 2018, $11.8 million in 2019, $6.3 million in 2020 and $0.7 million in 2021.

7. EARNINGS PER SHARE

Basic earnings per share is computed by dividing net income attributable to WESCO International by the weighted-average number of common shares outstanding during the periods. Diluted earnings per share is computed by dividing net income attributable to WESCO International by the weighted-average common shares and common share equivalents outstanding during the periods. The dilutive effect of common share equivalents is considered in the diluted earnings per share computation using the treasury stock method, which includes consideration of equity awards.

11

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS—(CONTINUED)

(unaudited)

The following table sets forth the details of basic and diluted earnings per share:

	Three Months Ended				Nine Months Ended
	September 30				September 30
(In thousands, except per share data)	2018		2017		2018		2017
Net income attributable to WESCO International	$	66,849	$	53,675	$	169,210	$	140,918
Weighted-average common shares outstanding used in computing basic earnings per share	47,010		47,415		47,044		48,134
Common shares issuable upon exercise of dilutive equity awards	476		389		503		508
Weighted-average common shares outstanding and common share equivalents used in computing diluted earnings per share	47,486		47,804		47,547		48,642
Earnings per share attributable to WESCO International
Basic	$	1.42	$	1.13	$	3.60	$	2.93
Diluted	$	1.41	$	1.12	$	3.56	$	2.90

For the three and nine months ended September 30, 2018 the computation of diluted earnings per share attributable to WESCO International excluded stock-based awards of approximately 1.7 million and 1.5 million, respectively. For the three and nine months ended September 30, 2017, the computation of diluted earnings per share attributable to WESCO International excluded stock-based awards of approximately 1.5 million and 1.3 million, respectively. These amounts were excluded because their effect would have been antidilutive.

In December 2014, the Company's Board of Directors authorized the repurchase of up to $300 million of the Company's common stock through December 31, 2017 (the "2014 Repurchase Authorization"). During the nine months ended September 30, 2017, the Company repurchased 1,778,537 shares under the 2014 Repurchase Authorization for $100.0 million.

In December 2017, the Company's Board of Directors authorized the repurchase of up to $300 million of the Company's common stock through December 31, 2020 (the "2017 Repurchase Authorization"). On September 6, 2018, the Company entered into an accelerated stock repurchase agreement (the "ASR Transaction") with a financial institution to repurchase additional shares of its common stock pursuant to its 2017 Repurchase Authorization. In exchange for an up-front cash payment of $25.0 million, the Company received an initial share delivery of 351,821 shares. As of September 30, 2018, the ASR Transaction had not yet settled between the counterparties. The total number of shares ultimately delivered under the ASR Transaction will be determined by the average of the volume-weighted average prices of the Company's common stock for each exchange business day during the settlement valuation period. For purposes of computing earnings per share for the three and nine months ended September 30, 2018 and 2017, share repurchases were reflected as a reduction to common shares outstanding on the respective delivery dates. WESCO funded the repurchase with available cash and borrowings under the Company's accounts receivable securitization facility.

8. EMPLOYEE BENEFIT PLANS

A majority of WESCO’s employees are covered by defined contribution retirement savings plans for their services rendered subsequent to WESCO’s formation. WESCO also offers a deferred compensation plan for select individuals. For U.S. participants, WESCO matches contributions made by employees at an amount equal to 50% of participants' total monthly contributions up to a maximum of 6% of eligible compensation. For Canadian participants, WESCO makes contributions in amounts ranging from 3% to 5% of participants' eligible compensation based on years of continuous service. WESCO may also make, subject to the Board of Directors' approval, a discretionary contribution to the defined contribution retirement savings plan covering U.S. participants if certain predetermined profit levels are attained. For the nine months ended September 30, 2018 and 2017, WESCO incurred charges of $33.5 million and $20.3 million, respectively, for all such plans. Contributions are made in cash to employee retirement savings plan accounts. The deferred compensation plan is an unfunded plan. As of September 30, 2018 and December 31, 2017, the Company's obligation under the deferred compensation plan was $23.8 million and $24.3 million, respectively. Employees have the option to transfer balances allocated to their accounts in the defined contribution retirement savings plan and the deferred compensation plan into any of the available investment options.

The Company sponsors a contributory defined benefit plan covering substantially all Canadian employees of EECOL and a Supplemental Executive Retirement Plan (the "SERP") for certain executives of EECOL. During the three and nine months ended September 30, 2018, the Company contributed $0.1 million and $0.3 million, respectively, to the SERP.

12

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS—(CONTINUED)

(unaudited)

The following table sets forth the components of net periodic benefit costs for the defined benefit plans:

	Three Months Ended						Nine Months Ended
	September 30						September 30
(In thousands)	2018			2017			2018			2017
Service cost	$	1,296		$	1,118		$	3,955		$	3,234
Interest cost	1,026			1,007			3,131			2,915
Expected return on plan assets	(1,482		)	(1,432		)	(4,522		)	(4,144		)
Recognized actuarial gain	(11		)	(51		)	(35		)	(149		)
Net periodic benefit cost	$	829		$	642		$	2,529		$	1,856

In accordance with ASU 2017-07, as described in Note 2, the service cost of $1.3 million and $4.0 million for the three and nine months ended September 30, 2018, respectively, was reported as a component of selling, general and administrative expenses. The other components of net periodic benefit cost totaling a net benefit of $0.5 million and $1.4 million for the three and nine months ended September 30, 2018, respectively, were presented as a component of net interest and other, as described in Note 9 below. For the three and nine months ended September 30, 2017, the Company reclassified a net benefit of $0.5 million and $1.4 million, respectively, from selling, general and administrative expenses to net interest and other. The Company used the amounts disclosed in Note 7 of the Notes to Condensed Consolidated Financial Statements in the Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2017 as the estimation basis for applying the retrospective presentation requirements.

9. NET INTEREST AND OTHER

Net interest and other includes interest expense, interest income, amortization of debt discount and debt issuance costs, the non-service cost components of net periodic benefit cost, and foreign exchange gains and losses from the remeasurement of certain financial instruments. For the three and nine months ended September 30, 2018, a foreign exchange gain of less than $0.1 million and a foreign exchange loss of $2.6 million, respectively, from the remeasurement of financial instruments were reported as a component of net interest and other. Foreign exchange gains and losses were not material for the three and nine months ended September 30, 2017.

10. COMMITMENTS AND CONTINGENCIES

From time to time, a number of lawsuits and claims have been or may be asserted against us relating to the conduct of our business, including routine litigation relating to commercial and employment matters. The outcome of any litigation cannot be predicted with certainty, and some lawsuits may be determined adversely to us. However, management does not believe that the ultimate outcome of any such pending matters is likely to have a material adverse effect on our financial condition or liquidity, although the resolution in any fiscal period of one or more of these matters may have a material adverse effect on our results of operations for that period.

11. INCOME TAXES

The effective tax rate for the three and nine months ended September 30, 2018 was 17.2% and 19.3%, respectively. The effective tax rate for the three and nine months ended September 30, 2017 was 25.5% and 25.3%, respectively. WESCO’s effective tax rate is typically impacted by the tax effect of intercompany financing, foreign tax rate differences, other nondeductible expenses and state income taxes. The effective tax rates for the current year periods are lower than the prior year periods primarily due to the Tax Cuts and Jobs Act of 2017 (the "TCJA"), which permanently reduced the U.S. federal statutory income tax rate from 35% to 21%, effective January 1, 2018. Also, the discrete benefits resulting from audit settlements favorably impacted the effective tax rate for the three months ended September 30, 2018.

The unaudited condensed consolidated financial information presented herein reflects provisional amounts for certain income tax effects of the TCJA for which the accounting is incomplete, but a reasonable estimate can be determined, based on enacted tax laws and rates as of September 30, 2018. Since the enactment of the TCJA on December 22, 2017, the Internal Revenue Service has issued proposed regulations and guidance regarding Section 965 of the Internal Revenue Code, as amended by the TCJA. We have reviewed the proposed regulations and guidance, and they do not materially impact the provisional amounts previously recorded for the one-time tax on the deemed repatriation of undistributed foreign earnings. Future adjustments (if any) resulting

13

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS—(CONTINUED)

(unaudited)

from additional regulatory guidance will be recognized as discrete income tax expense or benefit in the period the adjustments are determined.

The total amount of unrecognized tax benefits was reduced from $4.3 million to $1.6 million during the nine months ended September 30, 2018 due to audit settlements. The $1.6 million could affect the effective tax rate if recognized in the consolidated financial statements. It is reasonably possible that this amount will decrease by approximately $0.2 million within the next twelve months due to the expiration of statutes of limitation and the settlement of state audits.

12. CONDENSED CONSOLIDATING FINANCIAL INFORMATION

WESCO Distribution has outstanding $500 million in aggregate principal amount of 5.375% Senior Notes due 2021 (the "2021 Notes") and $350 million in aggregate principal amount of 5.375% Senior Notes due 2024 (the "2024 Notes"). The 2021 Notes and 2024 Notes are unsecured senior obligations of WESCO Distribution and are fully and unconditionally guaranteed on a senior unsecured basis by WESCO International.

Condensed consolidating financial information for WESCO International, WESCO Distribution and the non-guarantor subsidiaries is presented in the following tables.

	Condensed Consolidating Balance Sheet
	September 30, 2018
(In thousands)	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Cash and cash equivalents	$	—	$	57,052	$	85,708		$	—		$	142,760
Trade accounts receivable, net	—		—		1,265,880			—			1,265,880
Inventories	—		411,252		515,516			—			926,768
Prepaid expenses and other current assets	4,943		42,568		132,620			(9,040		)	171,091
Total current assets	4,943		510,872		1,999,724			(9,040		)	2,506,499
Intercompany receivables, net	—		—		2,270,584			(2,270,584		)	—
Property, buildings and equipment, net	—		56,351		100,778			—			157,129
Intangible assets, net	—		2,291		331,735			—			334,026
Goodwill	—		257,623		1,497,669			—			1,755,292
Investments in affiliates	3,188,872		5,144,891		—			(8,333,763		)	—
Other assets	—		2,780		23,065			—			25,845
Total assets	$	3,193,815	$	5,974,808	$	6,223,555		$	(10,613,387	)	$	4,778,791
Accounts payable	$	—	$	412,989	$	400,406		$	—		$	813,395
Short-term debt	—		—		31,125			—			31,125
Other current liabilities	—		72,762		143,286			(9,040		)	207,008
Total current liabilities	—		485,751		574,817			(9,040		)	1,051,528
Intercompany payables, net	952,642		1,317,942		—			(2,270,584		)	—
Long-term debt, net	—		864,779		364,535			—			1,229,314
Other noncurrent liabilities	3,820		117,464		144,828			—			266,112
Total WESCO International stockholders' equity	2,237,353		3,188,872		5,144,891			(8,333,763		)	2,237,353
Noncontrolling interests	—		—		(5,516		)	—			(5,516		)
Total liabilities and stockholders’ equity	$	3,193,815	$	5,974,808	$	6,223,555		$	(10,613,387	)	$	4,778,791

14

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS—(CONTINUED)

(unaudited)

	Condensed Consolidating Balance Sheet
	December 31, 2017
(In thousands)	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Cash and cash equivalents	$	—	$	50,602	$	67,351		$	—		$	117,953
Trade accounts receivable, net	—		—		1,170,080			—			1,170,080
Inventories	—		430,092		526,056			—			956,148
Prepaid expenses and other current assets	4,730		42,547		152,531			(35,140		)	164,668
Total current assets	4,730		523,241		1,916,018			(35,140		)	2,408,849
Intercompany receivables, net	—		—		2,189,136			(2,189,136		)	—
Property, buildings and equipment, net	—		50,198		106,247			—			156,445
Intangible assets, net	—		2,770		364,334			—			367,104
Goodwill	—		257,623		1,514,254			—			1,771,877
Investments in affiliates	3,058,613		5,023,826		—			(8,082,439		)	—
Other assets	—		2,778		28,415			—			31,193
Total assets	$	3,063,343	$	5,860,436	$	6,118,404		$	(10,306,715	)	$	4,735,468
Accounts payable	$	—	$	417,690	$	381,830		$	—		$	799,520
Short-term debt	—		—		34,075			—			34,075
Other current liabilities	—		80,039		162,475			(35,140		)	207,374
Total current liabilities	—		497,729		578,380			(35,140		)	1,040,969
Intercompany payables, net	939,784		1,249,352		—			(2,189,136		)	—
Long-term debt, net	—		934,033		379,228			—			1,313,261
Other noncurrent liabilities	3,820		120,709		140,566			—			265,095
Total WESCO International stockholders' equity	2,119,739		3,058,613		5,023,826			(8,082,439		)	2,119,739
Noncontrolling interests	—		—		(3,596		)	—			(3,596		)
Total liabilities and stockholders’ equity	$	3,063,343	$	5,860,436	$	6,118,404		$	(10,306,715	)	$	4,735,468

15

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS—(CONTINUED)

(unaudited)

	Condensed Consolidating Statement of Income and Comprehensive Income
	Three Months Ended
	September 30, 2018
(In thousands)	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—	$	899,994	$	1,206,174		$	(38,923	)	$	2,067,245
Cost of goods sold (excluding depreciation and
amortization)	—		727,052		981,908			(38,923		)	1,670,037
Selling, general and administrative expenses	—		149,390		134,683			—			284,073
Depreciation and amortization	—		4,475		11,143			—			15,618
Results of affiliates’ operations	66,645		61,771		—			(128,416		)	—
Net interest and other	—		13,127		3,923			—			17,050
Income tax expense	—		1,076		12,746			—			13,822
Net income	66,645		66,645		61,771			(128,416		)	66,645
Net loss attributable to noncontrolling interests	—		—		(204		)	—			(204		)
Net income attributable to WESCO International	$	66,645	$	66,645	$	61,975		$	(128,416	)	$	66,849
Other comprehensive income:
Foreign currency translation adjustments	20,486		20,486		20,486			(40,972		)	20,486
Comprehensive income attributable to WESCO International	$	87,131	$	87,131	$	82,461		$	(169,388	)	$	87,335

16

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS—(CONTINUED)

(unaudited)

	Condensed Consolidating Statement of Income and Comprehensive Income
	Nine Months Ended
	September 30, 2018
(In thousands)	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—		$	2,703,468		$	3,578,653		$	(116,967	)	$	6,165,154
Cost of goods sold (excluding depreciation and
amortization)	—			2,189,683			2,915,387			(116,967		)	4,988,103
Selling, general and administrative expenses	—			447,437			420,353			—			867,790
Depreciation and amortization	—			13,749			33,572			—			47,321
Results of affiliates’ operations	167,289			158,093			—			(325,382		)	—
Net interest and other	—			41,202			13,372			—			54,574
Income tax expense	—			2,201			37,876			—			40,077
Net income	167,289			167,289			158,093			(325,382		)	167,289
Net loss attributable to noncontrolling interests	—			—			(1,921		)	—			(1,921		)
Net income attributable to WESCO International	$	167,289		$	167,289		$	160,014		$	(325,382	)	$	169,210
Other comprehensive loss:
Foreign currency translation adjustments	(37,029		)	(37,029		)	(37,029		)	74,058			(37,029		)
Comprehensive income attributable to WESCO International	$	130,260		$	130,260		$	122,985		$	(251,324	)	$	132,181

17

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS—(CONTINUED)

(unaudited)

	Condensed Consolidating Statement of Income and Comprehensive Income
	Three Months Ended
	September 30, 2017
(In thousands)	WESCO International, Inc.		WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—	$	867,973		$	1,169,377		$	(37,191	)	$	2,000,159
Cost of goods sold (excluding depreciation and
amortization)	—		697,896			954,109			(37,191		)	1,614,814
Selling, general and administrative expenses	—		140,638			139,859			—			280,497
Depreciation and amortization	—		4,475			11,599			—			16,074
Results of affiliates’ operations	53,576		42,726			—			(96,302		)	—
Net interest and other	—		25,436			(8,601		)	—			16,835
Income tax (benefit) expense	—		(136		)	18,499			—			18,363
Net income	53,576		42,390			53,912			(96,302		)	53,576
Net loss attributable to noncontrolling interests	—		—			(99		)	—			(99		)
Net income attributable to WESCO International	$	53,576	$	42,390		$	54,011		$	(96,302	)	$	53,675
Other comprehensive income:
Foreign currency translation adjustments	51,148		51,148			51,148			(102,296		)	51,148
Comprehensive income attributable to WESCO International	$	104,724	$	93,538		$	105,159		$	(198,598	)	$	104,823

Reclassification

As described in Note 8, the Company reclassified a net benefit of $0.5 million from selling, general and administrative expenses to net interest and other in the previously reported Condensed Consolidated Statement of Income and Comprehensive Income of the non-guarantor subsidiaries for the three months ended September 30, 2017.

18

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS—(CONTINUED)

(unaudited)

	Condensed Consolidating Statement of Income and Comprehensive Income
	Nine Months Ended
	September 30, 2017
(In thousands)	WESCO International, Inc.		WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—	$	2,490,102		$	3,289,693		$	(97,420	)	$	5,682,375
Cost of goods sold (excluding depreciation and
amortization)	—		2,002,708			2,675,608			(97,420		)	4,580,896
Selling, general and administrative expenses	—		410,624			405,029			—			815,653
Depreciation and amortization	—		13,811			33,947			—			47,758
Results of affiliates’ operations	140,915		117,907			—			(258,822		)	—
Net interest and other	—		74,961			(25,492		)	—			49,469
Income tax (benefit) expense	—		(3,034		)	50,718			—			47,684
Net income	140,915		108,939			149,883			(258,822		)	140,915
Net loss attributable to noncontrolling interests	—		—			(3		)	—			(3		)
Net income attributable to WESCO International	$	140,915	$	108,939		$	149,886		$	(258,822	)	$	140,918
Other comprehensive income:
Foreign currency translation adjustments	96,097		96,097			96,097			(192,194		)	96,097
Post retirement benefit plan adjustments, net of tax	252		252			252			(504		)	252
Comprehensive income attributable to WESCO International	$	237,264	$	205,288		$	246,235		$	(451,520	)	$	237,267

Reclassification

As described in Note 8, the Company reclassified a net benefit of $1.4 million from selling, general and administrative expenses to net interest and other in the previously reported Condensed Consolidated Statement of Income and Comprehensive Income of the non-guarantor subsidiaries for the nine months ended September 30, 2017.

19

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS—(CONTINUED)

(unaudited)

	Condensed Consolidating Statement of Cash Flows
	Nine Months Ended
	September 30, 2018
(In thousands)	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net cash provided by operating activities	$	14,198		$	62,439		$	97,823		$	—		$	174,460
Investing activities:
Capital expenditures	—			(12,831		)	(10,918		)	—			(23,749		)
Dividends received from subsidiaries	—			118,271			—			(118,271		)	—
Other	—			(81,128		)	3,609			81,128			3,609
Net cash provided by (used in) investing activities	—			24,312			(7,309		)	(37,143		)	(20,140		)
Financing activities:
Borrowings	12,857			246,323			933,046			(81,128		)	1,111,098
Repayments	—			(318,323		)	(882,239		)	—			(1,200,562		)
Repurchases of common stock	(27,055		)	—			—			—			(27,055		)
Dividends paid by subsidiaries	—			—			(118,271		)	118,271			—
Other	—			(8,301		)	—			—			(8,301		)
Net cash used in financing activities	(14,198		)	(80,301		)	(67,464		)	37,143			(124,820		)
Effect of exchange rate changes on cash and cash equivalents	—			—			(4,693		)	—			(4,693		)
Net change in cash and cash equivalents	—			6,450			18,357			—			24,807
Cash and cash equivalents at the beginning of period	—			50,602			67,351			—			117,953
Cash and cash equivalents at the end of period	$	—		$	57,052		$	85,708		$	—		$	142,760

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WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS—(CONTINUED)

(unaudited)

	Condensed Consolidating Statement of Cash Flows
	Nine Months Ended
	September 30, 2017
(In thousands)	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net cash (used in) provided by operating activities	$	(28,740	)	$	168,603		$	(58,752	)	$	—		$	81,111
Investing activities:
Capital expenditures	—			(7,435		)	(8,535		)	—			(15,970		)
Dividends received from subsidiaries	—			51,561			—			(51,561		)	—
Other	—			(174,032		)	16,711			160,811			3,490
Net cash (used in) provided by investing activities	—			(129,906		)	8,176			109,250			(12,480		)
Financing activities:
Borrowings	135,442			557,391			691,682			(173,907		)	1,210,608
Repayments	—			(587,485		)	(617,301		)	13,096			(1,191,690		)
Repurchases of common stock	(106,702		)	—			—			—			(106,702		)
Dividends paid by subsidiaries	—			—			(51,561		)	51,561			—
Other	—			(4,380		)	—			—			(4,380		)
Net cash provided by (used in) financing activities	28,740			(34,474		)	22,820			(109,250		)	(92,164		)
Effect of exchange rate changes on cash and cash equivalents	—			—			7,485			—			7,485
Net change in cash and cash equivalents	—			4,223			(20,271		)	—			(16,048		)
Cash and cash equivalents at the beginning of period	—			41,552			68,579			—			110,131
Cash and cash equivalents at the end of period	$	—		$	45,775		$	48,308		$	—		$	94,083

13. SUBSEQUENT EVENTS

On October 31, 2018, the Company's Board of Directors approved an increase to the 2017 Repurchase Authorization from $300 million to $400 million, inclusive of the $25 million repurchase disclosed in Note 7 of these Notes to Condensed Consolidated Financial Statements.

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WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

Item 2.    Management's Discussion and Analysis of Financial Condition and Results of Operations.

The following discussion should be read in conjunction with the information in the unaudited condensed consolidated financial statements and notes thereto included herein and WESCO International, Inc.’s audited Consolidated Financial Statements and Management’s Discussion and Analysis of Financial Condition and Results of Operations included in its 2017 Annual Report on Form 10-K. The matters discussed herein may contain forward-looking statements that are subject to certain risks and uncertainties that could cause actual results to differ materially from expectations. Certain of these risks are set forth in WESCO International, Inc.'s Annual Report on Form 10-K for the fiscal year ended December 31, 2017, as well as WESCO International, Inc.’s other reports filed with the Securities and Exchange Commission.

Company Overview

WESCO International, Inc. (“WESCO International”), incorporated in 1993 and effectively formed in February 1994 upon acquiring a distribution business from Westinghouse Electric Corporation, is a leading North American-based distributor of products and provider of advanced supply chain management and logistics services used primarily in industrial, construction, utility, and commercial, institutional and government (“CIG”) markets. We are a leading provider of electrical, industrial, and communications maintenance, repair and operating ("MRO") and original equipment manufacturer ("OEM") products, construction materials, and advanced supply chain management and logistics services. Our primary product categories include general supplies, wire, cable and conduit, communications and security, electrical distribution and controls, lighting and sustainability, and automation, controls and motors.

We serve approximately 70,000 active customers globally through approximately 500 branches located primarily in the United States and Canada, with operations in 16 additional countries and 10 distribution centers located in the United States and Canada. We employ approximately 9,100 employees worldwide. We distribute over 1,000,000 products, grouped into six categories, from more than 26,000 suppliers, utilizing a highly automated, proprietary electronic procurement and inventory replenishment system.

In addition, we offer a comprehensive portfolio of value-added capabilities, which includes supply chain management, logistics and transportation, procurement, warehousing and inventory management, as well as kitting, limited assembly of products and system installation. Our value-added capabilities, extensive geographic reach, experienced workforce and broad product and supply chain solutions have enabled us to grow our business and establish a leading position in North America.

Our financial results for the first nine months of 2018 reflect sales growth, improved profitability as a result of favorable operating leverage, strong cash flow generation, as well as cost discipline and effective capital deployment. Net sales increased $482.8 million, or 8.5%, over the same period last year. Cost of goods sold as a percentage of net sales was 80.9% and 80.6% for the first nine months of 2018 and 2017, respectively. Selling, general and administrative ("SG&A") expenses as a percentage of net sales were 14.1% and 14.4% for the first nine months of 2018 and 2017, respectively. Operating profit was $261.9 million for the current nine month period, compared to $238.1 million for the first nine months of 2017. Operating profit increased primarily due to higher sales volume and cost control initiatives. Net income attributable to WESCO International for the nine months ended September 30, 2018 and 2017 was $169.2 million and $140.9 million, respectively.

Cash Flow

We generated $174.5 million of operating cash flow for the first nine months of 2018. Investing activities mostly consisted of $23.7 million of capital expenditures. Financing activities were comprised of borrowings and repayments of $504.3 million and $516.3 million, respectively, related to our revolving credit facility (the "Revolving Credit Facility"), borrowings and repayments of $490.0 million and $505.0 million, respectively, related to our accounts receivable securitization facility (the “Receivables Facility”) and repayments of $60.0 million applied to our term loan facility (the "Term Loan Facility"). Financing activities for the first nine months of 2018 also included borrowings and repayments on our various international lines of credit of approximately $116.8 million and $119.2 million, respectively. Additionally, financing activities for the first nine months of 2018 included the repurchase of $25.0 million of the Company's common stock pursuant to the share repurchase plan announced on December 13, 2017. Free cash flow for the first nine months of 2018 and 2017 was $150.8 million and $65.1 million, respectively.

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WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

The following table sets forth the components of free cash flow:

	Nine Months Ended
(In millions)	September 30, 2018			September 30, 2017
Cash flow provided by operations	$	174.5		$	81.1
Less: Capital expenditures	(23.7		)	(16.0		)
Free cash flow	$	150.8		$	65.1

Note: Free cash flow is a non-GAAP financial measure of liquidity. Capital expenditures are deducted from operating cash flow to determine free cash flow. Free cash flow is available to fund investing and financing activities.

Financing Availability

As of September 30, 2018, we had $562.8 million in total available borrowing capacity under our Revolving Credit Facility, which was comprised of $380.3 million of availability under the U.S. sub-facility and $182.5 million of availability under the Canadian sub-facility. Available borrowing capacity under our Receivables Facility was $185.0 million. The Revolving Credit Facility and the Receivables Facility both mature in September 2020.

Critical Accounting Policies and Estimates

Effective January 1, 2018, we adopted Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers, and all the related amendments, ASU 2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost,as well as certain other ASUs. See Note 2 of our Notes to the unaudited Condensed Consolidated Financial Statements for information regarding our critical accounting policies.

Results of Operations

Third Quarter of 2018 versus Third Quarter of 2017

The following table sets forth the percentage relationship to net sales of certain items in our Condensed Consolidated Statements of Income and Comprehensive Income for the periods presented:

	Three Months Ended
	September 30
	2018		2017
Net sales	100.0	%	100.0	%
Cost of goods sold (excluding depreciation and amortization)	80.8		80.7
Selling, general and administrative expenses (1)	13.7		14.0
Depreciation and amortization	0.8		0.8
Income from operations	4.7		4.5
Net interest and other (1)	0.8		0.9
Income before income taxes	3.9		3.6
Provision for income taxes	0.7		0.9
Net income attributable to WESCO International	3.2	%	2.7	%

⁽¹⁾  As described in Note 8 of the Notes to the unaudited Condensed Consolidated Financial Statements, we adopted Accounting Standards Update (ASU) 2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost, on a retrospective basis during the first quarter of 2018. This ASU requires the disaggregation of service cost from the other components of net periodic benefit cost. For the three months ended September 30, 2018 and 2017, the non-service cost components of net periodic benefit cost aggregated to a benefit of $0.5 million and are included in net interest and other.

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WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

Net sales were $2.1 billion for the third quarter of 2018, compared to $2.0 billion for the third quarter of 2017, an increase of 3.4%. Organic sales for the third quarter of 2018 grew by 4.2% as foreign exchange rates negatively impacted net sales by 0.8%.

The following table sets forth organic sales growth for the period presented:

	Three Months Ended
	September 30, 2018
Change in net sales	3.4	%
Impact from acquisitions	—	%
Impact from foreign exchange rates	(0.8	)%
Impact from number of workdays	—	%
Organic sales growth	4.2	%

Note: Organic sales growth is a non-GAAP financial measure of sales performance. Organic sales growth is calculated by deducting the percentage impact from acquisitions in the first year of ownership, foreign exchange rates and number of workdays from the overall percentage change in consolidated net sales.

Cost of goods sold for the third quarter of 2018 was $1.7 billion, compared to $1.6 billion for the third quarter of 2017. As a percentage of net sales, cost of goods sold was 80.8% and 80.7%, respectively. Cost of goods sold as a percentage of net sales for the third quarter of 2018 reflects margin improvement initiatives, which were more than offset by a reclassification of certain labor costs from SG&A to cost of goods sold.

SG&A expenses for the third quarter of 2018 totaled $284.1 million versus $280.5 million for the third quarter of 2017. As a percentage of net sales, SG&A expenses were 13.7% and 14.0%, respectively. SG&A expenses reflect higher payroll expenses and increased costs driven by sales volume growth, partially offset by gains from the sale of certain long-lived assets.

SG&A payroll expenses for the third quarter of 2018 of $204.8 million increased by $6.9 million compared to the same period in 2017 primarily due to higher sales volume and variable compensation expense, partially offset by a reclassification of certain labor costs from SG&A to cost of goods sold.

Depreciation and amortization for the third quarter of 2018 and 2017 was $15.6 million and $16.1 million, respectively.

Net interest and other totaled $17.1 million for the third quarter of 2018 compared to $16.8 million for the third quarter of 2017.

Income tax expense totaled $13.8 million for the third quarter of 2018 compared to $18.4 million in last year's comparable period and the effective tax rate was 17.2% and 25.5%, respectively. The lower effective tax rate in the current quarter is primarily due to the Tax Cuts and Jobs Act of 2017 (the "TCJA"), which permanently reduced the U.S. federal statutory income tax rate from 35% to 21%, effective January 1, 2018. Also, the discrete benefits resulting from audit settlements favorably impacted the effective tax rate for the third quarter of 2018.

Net income for the third quarter of 2018 was $66.6 million, compared to net income of $53.6 million for the third quarter of 2017.

Net loss of $0.2 million and $0.1 million was attributable to noncontrolling interests for the third quarter of 2018 and 2017, respectively. The change in loss attributable to noncontrolling interests was primarily due to the effect of foreign currency.

Net income and diluted earnings per share attributable to WESCO International were $66.8 million and $1.41 per share, respectively, for the third quarter of 2018, compared with net income and diluted earnings per share of $53.7 million and $1.12 per share, respectively, for the third quarter of 2017.

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WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

Nine Months EndedSeptember 30, 2018 versus Nine Months EndedSeptember 30, 2017

The following table sets forth the percentage relationship to net sales of certain items in our Condensed Consolidated Statements of Income and Comprehensive Income for the periods presented:

	Nine Months Ended
	September 30
	2018		2017
Net sales	100.0	%	100.0	%
Cost of goods sold (excluding depreciation and amortization)	80.9		80.6
Selling, general and administrative expenses (1)	14.1		14.4
Depreciation and amortization	0.8		0.8
Income from operations	4.2		4.2
Net interest and other (1)	0.8		0.9
Income before income taxes	3.4		3.3
Provision for income taxes	0.7		0.8
Net income attributable to WESCO International	2.7	%	2.5	%

⁽¹⁾  As described in Note 8 of the Notes to the unaudited Condensed Consolidated Financial Statements, we adopted Accounting Standards Update (ASU) 2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost, on a retrospective basis during the first quarter of 2018. This ASU requires the disaggregation of service cost from the other components of net periodic benefit cost. For the nine months ended September 30, 2018 and 2017, the non-service cost components of net periodic benefit cost aggregated to a benefit of $1.4 million and are included in net interest and other.

Net sales were $6.2 billion for the first nine months of 2018, compared to $5.7 billion for the first nine months of 2017, an increase of 8.5%. Organic sales for the first nine months of 2018 grew by 7.9% as foreign exchange rates positively impacted net sales by 0.6%.

The following table sets forth organic sales growth for the period presented:

	Nine Months Ended
	September 30, 2018
Change in net sales	8.5	%
Impact from acquisitions	—	%
Impact from foreign exchange rates	0.6	%
Impact from number of workdays	—	%
Organic sales growth	7.9	%

Note: Organic sales growth is a non-GAAP financial measure of sales performance. Organic sales growth is calculated by deducting the percentage impact from acquisitions in the first year of ownership, foreign exchange rates and number of workdays from the overall percentage change in consolidated net sales.

Cost of goods sold for the first nine months of 2018 was $5.0 billion, compared to $4.6 billion for the first nine months of 2017. As a percentage of net sales, cost of goods sold was 80.9% and 80.6%, respectively. The increase in cost of goods sold as a percentage of net sales was primarily due to geographic and end market business mix and a reclassification of certain labor costs from SG&A to cost of goods sold.

SG&A expenses for the first nine months of 2018 totaled $867.8 million versus $815.7 million for the first nine months of 2017. As a percentage of net sales, SG&A expenses were 14.1% and 14.4%, respectively. SG&A expenses reflect higher payroll expenses, increased costs driven by sales volume growth, a bad debt charge related to a Canadian customer that ceased operations, partially offset by gains from the sale of certain long-lived assets.

SG&A payroll expenses for the first nine months of 2018 of $608.7 million increased by $35.5 million compared to the same period in 2017 primarily due to higher sales volume and variable compensation expense, which was partially offset by a reclassification of certain labor costs from SG&A to cost of goods sold.

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WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

Depreciation and amortization for the first nine months of 2018 and 2017 was $47.3 million and $47.8 million, respectively.

Net interest and other totaled $54.6 million for the first nine months of 2018 compared to $49.4 million for the first nine months of 2017. The increase was primarily due to a foreign exchange loss of $2.6 million from the remeasurement of financial instruments, as well as accelerated amortization of debt discount and debt issuance costs related to early repayments on our term loan facility.

Income tax expense totaled $40.1 million for the first nine months of 2018 compared to $47.7 million in last year's comparable period and the effective tax rate was 19.3% and 25.3%, respectively. The lower effective tax rate in the current year is primarily due to the TCJA, which permanently reduced the U.S. federal statutory income tax rate from 35% to 21%, effective January 1, 2018.

Net income for the first nine months of 2018 was $167.3 million, compared to net income of $140.9 million for the first nine months of 2017.

Net loss of $1.9 million and less than $0.1 million was attributable to noncontrolling interests for the first nine months of 2018 and 2017, respectively. The change in net loss attributable to noncontrolling interests was primarily due to the effect of foreign currency.

Net income and diluted earnings per share attributable to WESCO International were $169.2 million and $3.56 per share, respectively, for the first nine months of 2018, compared with net income and diluted earnings per share of $140.9 million and $2.90 per share, respectively, for the first nine months of 2017.

Liquidity and Capital Resources

Total assets were $4.8 billion and $4.7 billion at September 30, 2018 and December 31, 2017, respectively. Total liabilities were $2.6 billion at September 30, 2018 and December 31, 2017. Total stockholders' equity was $2.2 billion at September 30, 2018 and $2.1 billion at December 31, 2017.

Our liquidity needs generally arise from fluctuations in our working capital requirements, capital expenditures, acquisitions and debt service obligations. As of September 30, 2018, we had $562.8 million in available borrowing capacity under our Revolving Credit Facility and $185.0 million in available borrowing capacity under our Receivables Facility, which combined with available cash of $79.8 million, provided liquidity of $827.6 million. Cash included in our determination of liquidity represents cash in deposit and interest bearing investment accounts. We believe cash provided by operations and financing activities will be adequate to cover our current operational and business needs. In addition, we regularly review our mix of fixed versus variable rate debt, and we may, from time to time, issue or retire borrowings and/or refinance existing debt in an effort to mitigate the impact of interest rate and foreign exchange rate fluctuations, and to maintain a cost-effective capital structure consistent with our anticipated capital requirements. At September 30, 2018, approximately 67% of our debt portfolio was comprised of fixed rate debt.

We monitor the depository institutions that hold our cash and cash equivalents on a regular basis, and we believe that we have placed our deposits with creditworthy financial institutions. We also communicate on a regular basis with our lenders regarding our financial and working capital performance, liquidity position and financial leverage. Our financial leverage ratio was 3.1 and 3.6 as of September 30, 2018 and December 31, 2017, respectively. In addition, we are in compliance with all covenants and restrictions contained in our debt agreements as of September 30, 2018.

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WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

The following table sets forth our financial leverage ratio as of September 30, 2018 and December 31, 2017:

	Twelve months ended
(In millions of dollars, except ratio)	September 30, 2018		December 31, 2017
Income from operations (1)	$	342.9	$	319.2
Depreciation and amortization	63.6		64.0
EBITDA	$	406.5	$	383.2
	September 30, 2018		December 31, 2017
Short-term borrowings and current debt	$	32.3	$	35.3
Long-term debt	1,229.3		1,313.3
Debt discount and debt issuance costs (2)	10.6		14.2
Total debt	1,272.2		1,362.8
Less: cash and cash equivalents	142.8		118.0
Total debt, net of cash	$	1,129.4	$	1,244.8
Financial leverage ratio	3.1		3.6
Financial leverage ratio, net of cash	2.8		3.2

⁽¹⁾  Due to the adoption of ASU 2017-07 on a retrospective basis in the first quarter of 2018, we classified the non-service cost components of net periodic benefit cost as part of net interest and other for the twelve months ended September 30, 2018 and December 31, 2017. These components aggregated to a benefit of $1.9 million and $1.8 million, respectively.

⁽²⁾  Long-term debt is presented in the condensed consolidated balance sheets net of debt discount and debt issuance costs.

Note: Financial leverage is a non-GAAP measure of the use of debt. Financial leverage ratio is calculated by dividing total debt, including debt discount and debt issuance costs, by EBITDA. Financial leverage ratio, net of cash is calculated by dividing total debt, including debt discount and debt issuance costs, net of cash, by EBITDA. EBITDA, which is also a non-GAAP financial measure, is defined as the trailing twelve months earnings before interest, taxes, depreciation and amortization.

At September 30, 2018, we had cash and cash equivalents totaling $142.8 million, of which $94.5 million was held by foreign subsidiaries. The cash held by our foreign subsidiaries could be subject to additional income taxes if repatriated. We continue to believe that we are able to maintain a sufficient level of liquidity for our domestic operations and commitments without repatriation of the cash held by these foreign subsidiaries. However, as a result of the TCJA, we are reevaluating our intent and ability to repatriate foreign cash based upon the available liquidity and cash flow needs of our foreign subsidiaries and will disclose in future filings any change in our intention to repatriate undistributed foreign earnings and any resulting income tax impacts.

We did not note any triggering events or substantive changes during the first nine months of 2018 that would require an interim evaluation of impairment of goodwill or indefinite-lived intangible assets. We will perform our annual impairment testing of goodwill and indefinite-lived intangible assets during the fourth quarter.

Over the next several quarters, we plan to closely manage working capital, and it is expected that excess cash will be directed primarily at growth initiatives, acquisitions, debt reduction, and share repurchases. We remain focused on maintaining ample liquidity and credit availability. We anticipate capital expenditures in 2018 to be higher than 2017 as we continue to invest in our business. We believe our balance sheet and ability to generate ample cash flow provides us with a durable business model and should allow us to fund growth initiatives and expansion needs.

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WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

Cash Flow

Operating Activities. Net cash provided by operating activities for the first nine months of 2018 totaled $174.5 million, compared with $81.1 million of cash generated for the first nine months of 2017. Net cash provided by operating activities included net income of $167.3 million and adjustments to net income totaling $67.1 million. Other sources of cash in the first nine months of 2018 included a decrease in inventories of $23.2 million, a decrease in other accounts receivable of $19.9 million, an increase in accounts payable of $18.2 million, an increase in accrued payroll and benefit costs of $2.8 million, and an increase other current and noncurrent liabilities of $2.3 million. Primary uses of cash in the first nine months of 2018 included: an increase in trade accounts receivable of $104.2 million resulting from higher sales; and, an increase in prepaid expenses and other assets of $22.1 million.

Net cash provided by operating activities for the first nine months of 2017 totaled $81.1 million, which included net income of $140.9 million and adjustments to net income totaling $68.8 million. Other sources of cash in 2017 included an increase in accounts payable of $138.3 million, a decrease in other accounts receivable of $4.4 million, and an increase in accrued payroll and benefit costs of $2.4 million. Primary uses of cash in 2017 included: an increase in trade accounts receivable of $174.7 million resulting from higher sales in the latter part of the first nine months of 2017; an increase in inventories of $86.7 million; an increase in prepaid expenses and other assets of $8.5 million; and, a decrease in other current and noncurrent liabilities of $3.8 million.

Investing Activities. Net cash used in investing activities for the first nine months of 2018 was $20.1 million, compared with $12.5 million used during the first nine months of 2017. Capital expenditures were $23.7 million for the nine month period ended September 30, 2018, compared to $16.0 million for the nine month period ended September 30, 2017.

Financing Activities. Net cash used in financing activities for the first nine months of 2018 was $124.9 million, compared to $92.2 million used in the first nine months of 2017. During the first nine months of 2018, financing activities consisted of borrowings and repayments of $504.3 million and $516.3 million, respectively, related to our Revolving Credit Facility, borrowings and repayments of $490.0 million and $505.0 million, respectively, related to our Receivables Facility and repayments of $60.0 million applied to our Term Loan Facility. Financing activities for the first nine months of 2018 also included borrowings and repayments on our various international lines of credit of approximately $116.8 million and $119.2 million, respectively. Additionally, financing activities for the first nine months of 2018 included the repurchase of $25.0 million of the Company's common stock pursuant to the share repurchase plan announced on December 13, 2017.

During the first nine months of 2017, financing activities consisted of borrowings and repayments of $589.5 million and $561.5 million, respectively, related to our Revolving Credit Facility, borrowings and repayments of $490.2 million and $470.2 million, respectively, related to our Receivables Facility, and repayments of $45.0 million applied to our Term Loan Facility. Financing activities for the first nine months of 2017 also included borrowings and repayments on our various international lines of credit of approximately $130.9 million and $115.0 million, respectively. Additionally, financing activities for the nine months ended September 30, 2017 included the repurchase of $106.7 million of the Company's common stock, of which $100.0 million was pursuant to the share repurchase plan announced on December 17, 2014.

Contractual Cash Obligations and Other Commercial Commitments

There were no material changes in our contractual obligations and other commercial commitments that would require an update to the disclosure provided in our 2017 Annual Report on Form 10-K. Management believes that cash generated from operations, together with amounts available under our Revolving Credit Facility and the Receivables Facility, will be sufficient to meet our working capital, capital expenditures and other cash requirements for the foreseeable future. However, there can be no assurances that this will continue to be the case.

Inflation

The rate of inflation, as measured by changes in the producer price index, affects different commodities, the cost of products purchased and ultimately the pricing of our different products and product classes to our customers. For the nine months ended September 30, 2018, pricing related to inflation impacted our sales by approximately 2%.

Seasonality

Our operating results are not significantly affected by seasonal factors. Sales during the first quarter are usually affected by a reduced level of activity. Sales during the second, third and fourth quarters are generally 6 - 8% higher than the first quarter. Sales typically increase beginning in March, with slight fluctuations per month through October. During periods of economic expansion or contraction, our sales by quarter have varied significantly from this pattern.

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WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

Impact of Recently Issued Accounting Standards

See Note 2 of our Notes to Condensed Consolidated Financial Statements for information regarding the effect of new accounting pronouncements.

Forward-Looking Statements

From time to time in this report and in other written reports and oral statements, references are made to expectations regarding our future performance. When used in this context, the words “anticipates,” “plans,” “believes,” “estimates,” “intends,” “expects,” “projects,” “will” and similar expressions may identify forward-looking statements, although not all forward-looking statements contain such words. Such statements including, but not limited to, our statements regarding business strategy, growth strategy, competitive strengths, productivity and profitability enhancement, competition, new product and service introductions and liquidity and capital resources are based on management’s beliefs, as well as on assumptions made by and information currently available to management, and involve various risks and uncertainties, some of which are beyond our control. Our actual results could differ materially from those expressed in any forward-looking statement made by us or on our behalf. In light of these risks and uncertainties, there can be no assurance that the forward-looking information will in fact prove to be accurate. Certain of these risks are set forth in the WESCO International’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017, as well as WESCO International’s other reports filed with the Securities and Exchange Commission. We have undertaken no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

Item 3.    Quantitative and Qualitative Disclosures about Market Risks.

There have not been any material changes to our exposures to market risk during the quarterly period ended September 30, 2018 that would require an update to the relevant disclosures provided in our 2017 Annual Report on Form 10-K.

Item 4.    Controls and Procedures.

Under the supervision and with the participation of our management, including our principal executive officer and principal financial officer, we conducted an evaluation of our disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)). Based on this evaluation, our principal executive officer and our principal financial officer concluded that our disclosure controls and procedures and internal control over financial reporting were effective as of the end of the period covered by this report.

Effective January 1, 2018, we adopted ASU 2014-09, Revenue from Contracts with Customers, and all the related amendments. Although the adoption of this new revenue standard had no impact on our results of operations, financial position or cash flows, we did expand our controls related to revenue recognition. However, there were no changes in our internal control over financial reporting that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

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WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

PART II—OTHER INFORMATION

Item 1. Legal Proceedings.

From time to time, a number of lawsuits and claims have been or may be asserted against us relating to the conduct of our business, including routine litigation relating to commercial and employment matters. The outcome of any litigation cannot be predicted with certainty, and some lawsuits may be determined adversely to us. However, management does not believe that the ultimate outcome of any such pending matters is likely to have a material adverse effect on our financial condition or liquidity, although the resolution in any fiscal period of one or more of these matters may have a material adverse effect on our results of operations for that period.

Item 1A. Risk Factors.

There have been no material changes to the risk factors previously disclosed in Item 1A. to Part 1 of WESCO’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017.

Item 2. Unregistered Sales of Equity Securities and Use of Proceeds.

The following table sets forth all issuer purchases of common stock during the three months ended September 30, 2018, including those made pursuant to publicly announced plans or programs:

Period	Total Number of Shares Purchased (2)	Average Price Paid Per Share		Total Number of Shares Purchased as Part of Publicly Announced Plans or Programs (1)	Approximate Dollar Value of Shares That May Yet be Purchased Under the Plans or Programs (1)
					(In Millions)
July 1 – July 31, 2018	60	$	58.25	—	$	300.0
August 1 – August 31, 2018	1,701	$	60.13	—	$	300.0
September 1 – September 30, 2018	352,785	$	60.40	351,821	$	275.0
Total	354,546	$	60.40	351,821

⁽¹⁾  On December 13, 2017, WESCO announced that its Board of Directors approved, on December 7, 2017, the repurchase of up to $300 million of the Company's common stock through December 31, 2020.

⁽²⁾  There were 2,725 shares purchased in the period that were not part of the publicly announced share repurchase program. These shares were surrendered by stock-based compensation plan participants to satisfy tax withholding obligations arising from the exercise of stock-settled stock appreciation rights and vesting of restricted stock units.

30

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

Item 6.Exhibits.

(a)Exhibits

(10)    Material Contracts

(1) Seventh Amendment to Fourth Amended and Restated Receivables Purchase Agreement, dated as of April 23, 2018

(31)    Rule 13a-14(a)/15d-14(a) Certifications

(1) Certification of Chief Executive Officer pursuant to Rules 13a-14(a) promulgated under the Exchange Act.

(2) Certification of Chief Financial Officer pursuant to Rules 13a-14(a) promulgated under the Exchange Act.

(32)    Section 1350 Certifications

(1) Certification of Chief Executive Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

(2) Certification of Chief Financial Officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.

101.INS    XBRL Instance Document.

101.SCH    XBRL Taxonomy Extension Schema Document.

101.CAL    XBRL Taxonomy Extension Calculation Linkbase Document.

101.DEF    XBRL Taxonomy Extension Definition Linkbase Document.

101.LAB    XBRL Taxonomy Extension Label Linkbase Document.

101.PRE    XBRL Taxonomy Extension Presentation Linkbase Document.

31

WESCO INTERNATIONAL, INC. AND SUBSIDIARIES

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

WESCO International, Inc.

(Registrant)

November 2, 2018	By:	/s/ David S. Schulz
(Date)		David S. Schulz
		Senior Vice President and Chief Financial Officer

32

EX-10.1

EXECUTION VERSION SEVENTH AMENDMENT TO FOURTH AMENDED AND RESTATED RECEIVABLES PURCHASE AGREEMENT THIS SEVENTH AMENDMENT TO FOURTH AMENDED AND RESTATED RECEIVABLES PURCHASE AGREEMENT (this “Amendment”), dated as of April 23, 2018, is entered into among WESCO RECEIVABLES CORP. (the “Seller”), WESCO DISTRIBUTION, INC. (“WESCO” or the “Servicer”), the Purchasers (each, a “Purchaser”) and Purchaser Agents (each, a “Purchaser Agent”) party hereto, and PNC BANK, NATIONAL ASSOCIATION, as Administrator (the “Administrator”). RECITALS 1. The Seller, the Servicer, each Purchaser, each Purchaser Agent and the Administrator are parties to the Fourth Amended and Restated Receivables Purchase Agreement, dated as of September 24, 2015 (as amended through the date hereof, the “Agreement”). 2. The parties hereto desire to amend the Agreement as hereinafter set forth. NOW THEREFORE, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties agree as follows: 1. Certain Defined Terms. Capitalized terms that are used herein without definition and that are defined in Exhibit I to the Agreement shall have the same meanings herein as therein defined. 2. Amendments to the Agreement. The agreement is hereby amended as follows: (a) The definition of “Eligible Receivable” set forth in Exhibit I is amended by adding the following new clause (r) and, in connection therewith, (i) deleting the word “and” at the end of clause (p) thereof and substituting “,” therefor and (ii) deleting the period at the end of clause (q) thereof and substituting “, and” therefor: (r) the Obligor of which is not DowDupont Inc. or any Subsidiary thereof. (b) The definition of “Excluded Receivable” set forth in Exhibit I to the Agreement is restated in its entirety as follows: “Excluded Receivable” means any Receivable (without giving effect to the exclusion of “Excluded Receivables” from the definition thereof) (i) owed by an Obligor not a resident of the United States and denominated in a currency other than U.S. dollars, (ii) the Obligor of which is Siemens AG or any Subsidiary thereof, (iii) the Obligor of which is Mondelez International Inc. or any Subsidiary thereof, (iv) owing by Ford Motor Company or any Subsidiary thereof, the Contract for which is the Energy Services Agreement, dated on or about December 29, 2017, between, inter alia, WESCO Distribution Inc. and Ford Motor Company 726757594 99551574

in connection with upgrades to the Rawsonville plant, (v) the Obligor is Dow Dupont Inc. or any Subsidiary thereof and which was originated on or after April 23, 2018 or (vi) the Contract for which is the Maintenance, Repair and Operating Supplies Agreement, dated on or about May 4, 2018, between, inter alia, WESCO Distribution Inc. and Dow Dupont Inc., owing by DowDupont Inc. (or any Subsidiary thereof) or any Person that is a successor in interest to DowDupont Inc. with respect to such Contract (or any Subsidiary thereof). 3. Representations and Warranties. The Seller and the Servicer hereby represent and warrant to each of the parties hereto as follows: (a) Representations and Warranties. The representations and warranties contained in Exhibit III of the Agreement, as amended hereby, are true and correct as of the date hereof. (b) No Default. Both before and immediately after giving effect to this Amendment and the transactions contemplated hereby, no Termination Event or Unmatured Termination Event exists or shall exist. 4. Effect of Amendment. All provisions of the Agreement, as expressly amended and modified by this Amendment shall remain in full force and effect. As of and after the Effective Time, all references in the Agreement (or in any other Transaction Document) to “this Agreement”, “hereof”, “herein” or words of similar effect referring to the Agreement shall be deemed to be references to the Agreement as amended by this Amendment. This Amendment shall not be deemed, either expressly or impliedly, to waive, amend or supplement any provision of the Agreement other than as set forth herein. 5. Effectiveness. This Amendment shall become effective as of the time (the “Effective Time”) at which the Administrator has executed this Amendment and receives each of the following, in each case form and substance satisfactory to the Administrator in its sole discretion: (A) counterparts of this Amendment executed by each of the other parties hereto and (B) such other agreements, documents, instruments and opinions as the Administrator may request. 6. Counterparts. This Amendment may be executed in any number of counterparts and by different parties on separate counterparts, each of which when so executed shall be deemed to be an original and all of which when taken together shall constitute but one and the same instrument. 7. Governing Law; Jurisdiction. 7.1 THIS AMENDMENT SHALL BE A CONTRACT MADE UNDER AND GOVERNED BY THE INTERNAL LAWS OF THE STATE OF NEW YORK (INCLUDING FOR SUCH PURPOSE SECTIONS 5-1401 AND 5-1402 OF THE GENERAL OBLIGATIONS LAW OF THE STATE OF NEW YORK). 2 726757594 99551574

7.2 ANY LEGAL ACTION OR PROCEEDING WITH RESPECT TO THIS AMENDMENT MAY BE BROUGHT IN THE COURTS OF THE STATE OF NEW YORK OR OF THE UNITED STATES FOR THE SOUTHERN DISTRICT OF NEW YORK; AND, BY EXECUTION AND DELIVERY OF THIS AMENDMENT, EACH OF THE PARTIES HERETO CONSENTS, FOR ITSELF AND IN RESPECT OF ITS PROPERTY, TO THE NON-EXCLUSIVE JURISDICTION OF THOSE COURTS. EACH OF THE PARTIES HERETO IRREVOCABLY WAIVES, TO THE MAXIMUM EXTENT PERMITTED BY LAW, ANY OBJECTION, INCLUDING ANY OBJECTION TO THE LAYING OF VENUE OR BASED ON THE GROUNDS OF FORUM NON CONVENIENS, THAT IT MAY NOW OR HEREAFTER HAVE TO THE BRINGING OF ANY ACTION OR PROCEEDING IN SUCH JURISDICTION IN RESPECT OF THIS AMENDMENT OR ANY DOCUMENT RELATED HERETO. EACH OF THE PARTIES HERETO WAIVES PERSONAL SERVICE OF ANY SUMMONS, COMPLAINT OR OTHER PROCESS, WHICH SERVICE MAY BE MADE BY ANY OTHER MEANS PERMITTED BY NEW YORK LAW. 8. Section Headings. The various headings of this Amendment are included for convenience only and shall not affect the meaning or interpretation of this Amendment, the Agreement or any provision hereof or thereof. [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK] 3 726757594 99551574

THE HUNTINGTON NATIONAL BANK, as a Committed Purchaser By: Name: Lynsey M. Sausaman Title: Assistant Vice President THE HUNTINGTON NATIONAL BANK, as Purchaser Agent for The Huntington National Bank By: Name: Lynsey M. Sausaman Title: Assistant Vice President S-5 Seventh Amendment to Fourth A&R RPA 726757594 99551574

LIBERTY STREET FUNDING LLC, as a Conduit Purchaser By: __________________________________ Name: __________________________________gáää=^K=oìëëç Title: __________________________________sáÅÉ=mêÉëáÇÉåí THE BANK OF NOVA SCOTIA, as a Committed Purchaser By: __________________________________ Name: __________________________________ Title: __________________________________ THE BANK OF NOVA SCOTIA, as Purchaser Agent for The Bank of Nova Scotia and Liberty Street Funding LLC By: __________________________________ Name: __________________________________ Title: __________________________________ S-6 Seventh Amendment to Fourth A&R RPA 726757594 99551574

EX-31.1

Exhibit 31.1

CERTIFICATION

     I, John J. Engel, certify that:

     1.      I have reviewed this quarterly report on Form 10-Q of WESCO International, Inc.;

     2.     Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

     3.     Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

     4.      The registrant's other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

    (a)      Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

    (b)      Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

    (c)      Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

    (d)      Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

     5.      The registrant's other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

    (a)      All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

(b) Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Date:	November 2, 2018	By:	/s/ John J. Engel
			John J. Engel
			Chairman, President and Chief Executive Officer

EX-31.2

Exhibit 31.2

CERTIFICATION

     I, David S. Schulz, certify that:

     1.      I have reviewed this quarterly report on Form 10-Q of WESCO International, Inc.;

     2.     Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

     3.     Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

     4.      The registrant's other certifying officer(s) and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

    (a)      Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

    (b)      Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

    (c)      Evaluated the effectiveness of the registrant's disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

    (d)      Disclosed in this report any change in the registrant's internal control over financial reporting that occurred during the registrant's most recent fiscal quarter (the registrant's fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting; and

     5.      The registrant's other certifying officer(s) and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant's auditors and the audit committee of the registrant's board of directors (or persons performing the equivalent functions):

    (a)      All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant's ability to record, process, summarize and report financial information; and

    (b)      Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant's internal control over financial reporting.

Date:	November 2, 2018	By:	/s/ David S. Schulz
			David S. Schulz
			Senior Vice President and Chief Financial Officer

EX-32.1

Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of WESCO International, Inc. (the “Company”) on Form 10-Q for the period ended September 30, 2018 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), the undersigned, in the capacity and on the date indicated below, hereby certifies pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to his knowledge:

1. The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operation of the Company.

November 2, 2018	By:	/s/ John J. Engel
		John J. Engel
		Chairman, President and Chief Executive Officer

EX-32.2

Exhibit 32.2

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of WESCO International, Inc. (the “Company”) on Form 10-Q for the period ended September 30, 2018 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), the undersigned, in the capacity and on the date indicated below, hereby certifies pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to his knowledge:

1. The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

2. The information contained in the Report fairly presents, in all material respects, the financial condition and results of operation of the Company.

November 2, 2018	By:	/s/ David S. Schulz
		David S. Schulz
		Senior Vice President and Chief Financial Officer

XML

DOCUMENT AND ENTITY INFORMATION Document - shares	9 Months Ended
	Sep. 30, 2018	Nov. 01, 2018
Entity [Abstract]
Entity Registrant Name	WESCO INTERNATIONAL INC.
Entity Central Index Key	0000929008
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		46,691,008
Entity Current Reporting Status	Yes
Entity Emerging Growth Company	false
Entity Small Business	false

XML

CONSOLIDATED BALANCE SHEETS $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Depreciation, Depletion and Amortization, Nonproduction	$ 15,618	$ 47,321
Other Accrued Liabilities, Current	102,489	102,489	$ 95,820
Current Assets:
Cash and cash equivalents	142,760	142,760	117,953
Allowance for Doubtful Accounts Receivable, Current	25,272	25,272	21,313
Trade accounts receivable, net of allowance for doubtful accounts of $23,069 and $19,309 in 2014 and 2013, respectively	1,265,880	1,265,880	1,170,080
Accounts and Other Receivables, Net, Current	80,676	80,676	101,229
Inventories, net	926,768	926,768	956,148
Prepaid expenses and other current assets	90,415	90,415	63,439
Total current assets	2,506,499	2,506,499	2,408,849
Property, buildings and equipment, net of accumulated depreciation of $229,041 and $213,758 in 2014 and 2013, respectively	157,129	157,129	156,445
Intangible assets, net	334,026	334,026	367,104
Goodwill	1,755,292	1,755,292	1,771,877
Other assets	25,845	25,845	31,193
Total assets	4,778,791	4,778,791	4,735,468
Current Liabilities:
Accounts payable	813,395	813,395	799,520
Accrued payroll and benefit costs	73,074	73,074	72,686
Short-term debt	31,125	31,125	34,075
Current portion of long-term debt	1,179	1,179	1,224
Total current liabilities	1,051,528	1,051,528	1,040,969
Long-term Debt, Excluding Current Maturities	1,229,314	1,229,314	1,313,261
Other noncurrent liabilities	119,064	119,064	128,237
Deferred Tax Liabilities, Net, Noncurrent	147,048	147,048	136,858
Total liabilities	2,546,954	2,546,954	2,619,325
Commitments and Contingencies
Bank Overdrafts	30,266	30,266	37,644
Stockholders' Equity:
Preferred stock, $.01 par value; 20,000,000 shares authorized, no shares issued or outstanding	0	0	0
Additional capital	1,006,222	1,006,222	999,156
Retained earnings	2,249,327	2,249,327	2,079,697
Treasury stock, at cost; 18,247,467 and 18,179,275 shares in 2014 and 2013, respectively	(669,212)	(669,212)	(647,158)
Accumulated other comprehensive income	(349,619)	(349,619)	(312,590)
Total WESCO International stockholders' equity	2,231,837	2,231,837	2,116,143
Noncontrolling interest	(5,516)	(5,516)	(3,596)
Total stockholders' equity	2,237,353	2,237,353	2,119,739
Total liabilities and stockholders' equity	4,778,791	4,778,791	4,735,468
Common Stock [Member]
Stockholders' Equity:
Common stock	592	592	591
Common Class B [Member]
Stockholders' Equity:
Common stock	$ 43	$ 43	$ 43

XML

CONSOLIDATED BALANCE SHEETS (Parentheticals) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Allowance for doubtful accounts	$ 25,272,000	$ 21,313,000
Accumulated depreciation	289,273,000	278,455,000
Finite-Lived Intangible Assets, Accumulated Amortization	248,797	223,554
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	$ 10,596,000	$ 14,224,000
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Treasury stock, shares (in shares)	16,738,766	16,375,653
Common Stock [Member]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	210,000,000	210,000,000
Common stock, shares, issued (in shares)	59,152,810	59,045,762
Common stock, shares outstanding (in shares)	46,753,475	47,009,540
Common Class B [Member]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	20,000,000	20,000,000
Common stock, shares, issued (in shares)	4,339,431	4,339,431
Common stock, shares outstanding (in shares)	0	0

XML

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues	$ 2,067,245	$ 2,000,159	$ 6,165,154	$ 5,682,375
Cost of goods sold	1,670,037	1,614,814	4,988,103	4,580,896
Selling, general and administrative expense	284,073	280,497	867,790	815,653
Depreciation and amortization	15,618	16,074	47,321	47,758
Income from operations	97,517	88,774	261,940	238,068
Nonoperating Income (Expense)	17,050	16,835	54,574	49,469
Income before income taxes	80,467	71,939	207,366	188,599
Provision for income taxes	13,822	18,363	40,077	47,684
Net income	66,645	53,576	167,289	140,915
Net (loss) income attributable to noncontrolling interest	(204)	(99)	(1,921)	(3)
Net income attributable to WESCO International, Inc.	66,849	53,675	169,210	140,918
Comprehensive Income:
Foreign currency translation adjustment	20,486	51,148	(37,029)	96,097
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	0	0	0	252
Comprehensive income attributable to WESCO International, Inc.	$ 87,335	$ 104,823	$ 132,181	$ 237,267
Earnings per share attributable to WESCO International, Inc.
Basic (in dollars per share)	$ 1.42	$ 1.13	$ 3.60	$ 2.93
Diluted (in dollars per share)	$ 1.41	$ 1.12	$ 3.56	$ 2.90
Shipping and Handling [Member]
Cost of goods sold	$ 18,800	$ 15,500	$ 55,600	$ 43,200

XML

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Statement of Cash Flows [Abstract]
Interest Paid, Including Capitalized Interest, Operating and Investing Activities	$ 37,138	$ 35,344
Operating Activities:
Net income	167,289	140,915
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	47,321	47,758
Deferred income taxes	12,194	8,433
Other operating activities, net	7,590	12,617
Changes in assets and liabilities
Increase (Decrease) in Accounts Receivable	104,215	174,667
Increase (Decrease) in Accounts and Other Receivables	(19,859)	(4,421)
Inventories, net	23,189	(86,736)
Prepaid expenses and other current assets	(22,088)	(8,515)
Accounts payable	18,235	138,348
Accrued payroll and benefit costs	2,788	2,383
Other current and noncurrent liabilities	2,298	(3,846)
Net cash provided by operating activities	174,460	81,111
Investing Activities:
Capital expenditures	(23,749)	(15,970)
Other investing activities	3,609	3,490
Net cash used in investing activities	(20,140)	(12,480)
Financing Activities:
Proceeds from issuance of short-term debt	116,775	130,890
Repayments of short-term debt	(119,239)	(114,972)
Proceeds from issuance of long-term debt	994,323	1,079,718
Repayments of Long-term Debt	(1,081,323)	(1,076,718)
Other financing activities, net	(8,301)	(4,380)
Net cash used in financing activities	(124,820)	(92,164)
Payments for Repurchase of Common Stock	(27,055)	(106,702)
Effect of exchange rate on cash and cash equivalents	(4,693)	7,485
Net change in cash and cash equivalents	24,807	(16,048)
Cash and cash equivalents at the beginning of period	117,953	110,131
Cash and cash equivalents at the end of period	142,760	94,083
Income Taxes Paid	$ 48,744	$ 50,909

XML

ORGANIZATION

9 Months Ended

Sep. 30, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

ORGANIZATION

1. ORGANIZATION

WESCO International, Inc. ("WESCO International") and its subsidiaries (collectively, “WESCO” or the "Company"), headquartered in Pittsburgh, Pennsylvania, is a full-line distributor of electrical, industrial and communications maintenance, repair and operating ("MRO") and original equipment manufacturer ("OEM") products, construction materials, and advanced supply chain management and logistics services used primarily in the industrial, construction, utility and commercial, institutional and government markets. WESCO serves approximately 70,000 active customers globally through approximately 500 branches and 10 distribution centers located primarily in the United States and Canada, with operations in 16 additional countries.

XML

ACCOUNTING POLICIES

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

ACCOUNTING POLICIES

2. ACCOUNTING POLICIES

Basis of Presentation

The accompanying unaudited Condensed Consolidated Financial Statements of WESCO have been prepared in accordance with Rule 10-01 of Regulation S-X of the Securities and Exchange Commission (the “SEC”). The unaudited condensed consolidated financial information should be read in conjunction with the audited Consolidated Financial Statements and Notes thereto included in WESCO’s 2017 Annual Report on Form 10-K as filed with the SEC on February 22, 2018. The Condensed Consolidated Balance Sheet at December 31, 2017 was derived from the audited Consolidated Financial Statements as of that date, but does not include all of the disclosures required by accounting principles generally accepted in the United States of America.

The unaudited Condensed Consolidated Balance Sheet as of September 30, 2018, the unaudited Condensed Consolidated Statements of Income and Comprehensive Income for the nine months ended September 30, 2018 and 2017, respectively, and the unaudited Condensed Consolidated Statements of Cash Flows for the nine months ended September 30, 2018 and 2017, respectively, in the opinion of management, have been prepared on the same basis as the audited Consolidated Financial Statements and include all adjustments necessary for the fair statement of the results of the interim periods presented herein. All adjustments reflected in the unaudited condensed consolidated financial information are of a normal recurring nature unless indicated. The results for the interim periods presented herein are not necessarily indicative of the results to be expected for the full year.

Reclassifications

Effective January 1, 2018, WESCO adopted Accounting Standards Update (ASU) 2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The adoption of this ASU, as described below and in Note 8, resulted in the reclassification of amounts reported in the unaudited Condensed Consolidated Statements of Income and Comprehensive Income for the three and nine months ended September 30, 2017.

Recently Adopted Accounting Pronouncements

Effective January 1, 2018, WESCO adopted ASU 2014-09, Revenue from Contracts with Customers, and all the related amendments (“Topic 606”) using the modified retrospective approach to all open contracts. There was no impact to WESCO’s previously reported consolidated financial statements and WESCO does not expect the adoption of Topic 606 to have a material impact on its revenue and results of operations on an ongoing basis.

WESCO’s significant accounting policies are disclosed in Note 2 of the Notes to Consolidated Financial Statements in the Annual Report on Form 10-K for the year ended December 31, 2017. Changes to the Company’s significant accounting policies as a result of adopting Topic 606 are described in Note 3 below.

In August 2016, the Financial Accounting Standards Board (FASB) issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force). This ASU provides guidance on eight specific cash flow issues where there is diversity in practice. The Company adopted this ASU in the first quarter of 2018. The adoption of this guidance did not have an impact on the unaudited condensed consolidated financial information presented herein.

In March 2017, the FASB issued ASU 2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. This ASU requires that an employer disaggregate the service cost from the other components of net benefit cost. The Company adopted this guidance on a retrospective basis in the first quarter of 2018. See Note 8 for a description of the impact of this accounting standard on the unaudited Condensed Consolidated Statements of Income and Comprehensive Income presented herein. The adoption of this guidance did not have an impact on the Company's unaudited Condensed Consolidated Balance Sheets and the unaudited Condensed Consolidated Statements of Cash Flows presented herein.

In May 2017, the FASB issued ASU 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting. This ASU clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions, or the classification of the award (as equity or liability) changes as a result of the change in terms or conditions. The Company adopted this ASU in the first quarter of 2018. The adoption of this guidance did not have an impact on the unaudited condensed consolidated financial information presented herein.

Recently Issued Accounting Pronouncements

In February 2016, the FASB issued ASU 2016-02, Leases, a comprehensive new standard that amends various aspects of existing accounting guidance for leases, including the recognition of a right-of-use asset and a lease liability in the balance sheet and disclosing key information about leasing arrangements. This ASU is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. During 2018, the FASB issued additional ASUs that address implementation issues and correct or improve certain aspects of the new accounting guidance for leases, including ASU 2018-10, Codification Improvements to Topic 842, Leases and ASU 2018-11, Leases (Topic 842): Targeted Improvements. These ASUs do not change the core principles in the leasing standard outlined above. The amendments in ASU 2018-11 provide an optional transition method that allows entities to initially apply the new leases standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. Consequently, an entity’s reporting for the comparative periods will continue to be in accordance with current lease accounting guidance. Management established a cross-functional team to evaluate and implement the new standard. The team selected a third-party software solution to facilitate the accounting and financial reporting requirements of the new lease standard. Lease data elements have been gathered and are currently being migrated to the software solution. The new standard will be adopted in the first quarter of 2019 and the Company expects to use the optional transition method. While the Company has not yet completed its evaluation of the effects of adopting this ASU, right-of-use assets and lease liabilities will be recorded in the Consolidated Balance Sheets as of the effective date and thereafter.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which introduces new guidance for the accounting for credit losses on certain financial instruments. The amendments in this ASU are effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted. Management does not expect the adoption of this accounting standard to have a material impact on its consolidated financial statements and notes thereto.

In January 2017, the FASB issued ASU 2017-04, Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment, which eliminates Step 2 of the goodwill impairment test. Under the amendments in this ASU, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. An entity should apply the amendments in this ASU on a prospective basis. This guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Management expects to adopt this ASU in the fourth quarter of 2018 when the Company performs its annual impairment testing. The Company does not expect the adoption of this accounting standard to have a material impact on its consolidated financial statements and notes thereto.

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement, which amends the disclosure requirements for recurring and nonrecurring fair value measurements by removing, modifying and adding certain disclosures. The amendments in this ASU are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted. Management does not expect the adoption of this accounting standard to have a material impact on its consolidated financial statements and notes thereto.

In August 2018, the FASB issued ASU 2018-14, Compensation—Retirement Benefits—Defined Benefit Plans—General (Subtopic 715-20): Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans, which amends the disclosure requirements for all employers that sponsor defined benefit pension and other post retirement plans by removing and adding certain disclosures. The amendments in this ASU are effective for fiscal years ending after December 15, 2020. Early adoption is permitted. Management does not expect the adoption of this accounting standard to have a material impact on its consolidated financial statements and notes thereto.

Other pronouncements issued by the FASB or other authoritative accounting standards groups with future effective dates are either not applicable or are not expected to be significant to WESCO’s financial position, results of operations or cash flows.

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ACQUISITIONS

9 Months Ended

Sep. 30, 2018

Business Combinations [Abstract]

ACQUISITIONS

3. REVENUE

WESCO’s revenue arrangements generally consist of single performance obligations to transfer a promised good or service, or a combination of goods and services. Revenue is recognized when control has transferred to the customer, which is generally when the product has shipped from a WESCO facility or directly from a supplier. For products that ship directly from suppliers to customers, WESCO acts as the principal in the transaction and recognizes revenue on a gross basis. Revenue for integrated supply services is recognized over time based on hours incurred. This method reflects the transfer of control as the customer benefits from these services as they are being performed. WESCO generally satisfies its performance obligations within a year or less.

WESCO generally does not have significant financing terms associated with its contracts; payments are normally received within 60 days. There are no significant costs associated with obtaining customer contracts. WESCO generally passes through the warranties offered by the applicable manufacturer or supplier to its customers. Sales taxes (and value added taxes in foreign jurisdictions) collected from customers and remitted to governmental authorities are excluded from net sales.

The following tables disaggregate WESCO’s revenue by end market and geography:

	Three Months Ended				Nine Months Ended
	September 30				September 30
(In thousands)	2018		2017		2018		2017
Industrial	$	723,869	$	722,227	$	2,243,590	$	2,111,813
Construction	686,165		674,996		2,007,708		1,870,406
Utility	345,937		312,501		998,438		861,162
Commercial, Institutional and Government ("CIG")	311,274		290,435		915,418		838,994
Total by end market	$	2,067,245	$	2,000,159	$	6,165,154	$	5,682,375

	Three Months Ended				Nine Months Ended
	September 30				September 30
(In thousands)	2018		2017		2018		2017
United States	$	1,525,393	$	1,473,016	$	4,571,533	$	4,267,684
Other (1)	541,852		527,143		1,593,621		1,414,691
Total by geography	$	2,067,245	$	2,000,159	$	6,165,154	$	5,682,375

⁽¹⁾  Other primarily includes net sales originating in Canada.

WESCO distributes products and provides services to customers globally within the following end markets: (1) industrial, (2) construction, (3) utility, and (4) CIG. Revenue is measured as the amount of consideration WESCO expects to receive in exchange for transferring goods or providing services.

In accordance with certain contractual arrangements, WESCO receives payment from its customers in advance and recognizes such payment as deferred revenue. Revenue for advance payment is recognized when the performance obligation has been satisfied and control has transferred to the customer, which is generally upon shipment. Deferred revenue is usually recognized within a year or less from the date of the customer’s advance payment. At September 30, 2018 and December 31, 2017, $8.8 million and $15.5 million, respectively, of deferred revenue was recorded as a component of other current liabilities in the Condensed Consolidated Balance Sheets.

WESCO’s revenues are adjusted for variable consideration, which includes customer volume rebates, returns, and discounts. WESCO measures variable consideration by estimating expected outcomes using analysis and inputs based upon anticipated performance, historical data, as well as current and forecasted information. Measurement and recognition of variable consideration is reviewed by management on a monthly basis and revenue is adjusted accordingly. Variable consideration reduced revenue for the three months ended September 30, 2018 and 2017 by approximately $25.1 million and $24.2 million, respectively, and by approximately $74.5 million and $66.5 million for the nine months ended September 30, 2018 and 2017, respectively.

Shipping and handling costs are recognized in net sales when they are billed to the customer. These costs are recognized as a component of selling, general and administrative expenses when WESCO does not bill the customer. WESCO has elected to recognize shipping and handling costs as a fulfillment cost. Shipping and handling costs recorded as a component of selling, general and administrative expenses totaled $18.8 million and $15.5 million for the three months ended September 30, 2018 and 2017, respectively, and $55.6 million and $43.2 million for the nine months ended September 30, 2018 and 2017, respectively.

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STOCK-BASED COMPENSATION

9 Months Ended

Sep. 30, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

STOCK-BASED COMPENSATION

6. STOCK-BASED COMPENSATION

WESCO’s stock-based employee compensation plans are comprised of stock-settled stock appreciation rights, restricted stock units and performance-based awards. Compensation cost for all stock-based awards is measured at fair value on the date of grant and compensation cost is recognized, net of estimated forfeitures, over the service period for awards expected to vest. The fair value of stock-settled stock appreciation rights and performance-based awards with market conditions is determined using the Black-Scholes and Monte Carlo simulation models, respectively. The fair value of restricted stock units and performance-based awards with performance conditions is determined by the grant-date closing price of WESCO’s common stock. The forfeiture assumption is based on WESCO’s historical employee behavior that is reviewed on an annual basis. No dividends are assumed.

Effective January 1, 2018, performance-based awards are based on two equally-weighted performance measures, which include the three-year average growth rate of the Company’s fully diluted earnings per share and the three-year cumulative return on net assets. From 2015 to 2017, the two equally-weighted performance-based award metrics were the three-year average growth rate of WESCO's net income and WESCO's total stockholder return in relation to the total stockholder return of a select group of peer companies over a three-year period.

During the three and nine months ended September 30, 2018 and 2017, WESCO granted the following stock-settled stock appreciation rights, restricted stock units and performance-based awards at the following weighted-average fair values:

	Three Months Ended				Nine Months Ended
	September 30, 2018		September 30, 2017		September 30, 2018		September 30, 2017
Stock-settled stock appreciation rights granted	9,415		12,076		509,046		455,807
Weighted-average fair value	$	17.40	$	15.74	$	18.38	$	20.52
Restricted stock units granted	2,686		2,313		119,457		100,993
Weighted-average fair value	$	61.41	$	57.30	$	62.72	$	71.33
Performance-based awards granted	—		—		44,144		39,978
Weighted-average fair value	$	—	$	—	$	62.80	$	76.63

The fair value of stock-settled stock appreciation rights was estimated using the following weighted-average assumptions:

	Three Months Ended				Nine Months Ended
	September 30, 2018		September 30, 2017		September 30, 2018		September 30, 2017
Risk free interest rate	2.8	%	1.8	%	2.5	%	1.9	%
Expected life (in years)	5		5		5		5
Expected volatility	28	%	28	%	28	%	29	%

The risk-free interest rate is based on the U.S. Treasury Daily Yield Curve as of the grant date. The expected life is based on historical exercise experience and the expected volatility is based on the volatility of the Company's daily stock prices over a five-year period preceding the grant date.

The following table sets forth a summary of stock-settled stock appreciation rights and related information for the nine months ended September 30, 2018:

	Awards		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (In years)	Aggregate Intrinsic Value (In thousands)
Outstanding at December 31, 2017	2,238,607		$	57.75
Granted	509,046		62.68
Exercised	(186,662	)	40.73
Forfeited	(168,824	)	69.12
Outstanding at September 30, 2018	2,392,167		59.32		6.3	$	16,779
Exercisable at September 30, 2018	1,476,763		$	58.03	4.9	$	13,566

The following table sets forth a summary of time-based restricted stock units and related information for the nine months ended September 30, 2018:

	Awards		Weighted- Average Fair Value
Unvested at December 31, 2017	290,054		$	58.11
Granted	119,457		62.72
Vested	(59,905	)	68.78
Forfeited	(14,539	)	57.09
Unvested at September 30, 2018	335,067		$	57.89

Performance shares are awards for which the vesting will occur based on market or performance conditions. The following table sets forth a summary of performance-based awards for the nine months ended September 30, 2018:

	Awards		Weighted- Average Fair Value
Unvested at December 31, 2017	148,508		$	60.23
Granted	44,144		62.80
Vested	—		—
Forfeited	(52,342	)	65.15
Unvested at September 30, 2018	140,310		$	59.20

The fair value of the performance shares granted during the nine months ended September 30, 2018 and 2017 was estimated using the following weighted-average assumptions:

	Nine Months Ended
	September 30, 2018		September 30, 2017
Grant date share price	$	62.80	$	71.65
WESCO expected volatility	n/a		29		%
Peer group median volatility	n/a		24		%
Risk-free interest rate	n/a		1.5		%
Correlation of peer company returns	n/a		114		%

The unvested performance-based awards in the table above include 48,805 shares in which vesting of the ultimate number of shares is dependent upon WESCO's total stockholder return in relation to the total stockholder return of a select group of peer companies over a three-year period. These awards are accounted for as awards with market conditions; compensation cost is recognized over the service period, regardless of whether the market conditions are achieved and the awards ultimately vest.

Vesting of the remaining 91,505 shares of performance-based awards in the table above is dependent upon the achievement of certain performance targets, including 48,805 that are dependent upon the three-year average growth rate of WESCO's net income, 21,350 that are dependent upon the three-year average growth rate of the Company's fully diluted earnings per share, and 21,350 that are based upon the three-year cumulative return on net assets. These awards are accounted for as awards with performance conditions; compensation cost is recognized over the performance period based upon WESCO's determination of whether it is probable that the performance targets will be achieved.

WESCO recognized $4.1 million and $3.5 million of non-cash stock-based compensation expense, which is included in selling, general and administrative expenses, for the three months ended September 30, 2018 and 2017, respectively. WESCO recognized $12.1 million and $11.3 million of non-cash stock-based compensation expense, which is included in selling, general and administrative expenses, for the nine months ended September 30, 2018 and 2017, respectively. As of September 30, 2018, there was $22.9 million of total unrecognized compensation cost related to non-vested stock-based compensation arrangements for all awards previously made, of which approximately $4.1 million is expected to be recognized over the remainder of 2018, $11.8 million in 2019, $6.3 million in 2020 and $0.7 million in 2021.

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EARNINGS PER SHARE

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

EARNINGS PER SHARE

7. EARNINGS PER SHARE

Basic earnings per share is computed by dividing net income attributable to WESCO International by the weighted-average number of common shares outstanding during the periods. Diluted earnings per share is computed by dividing net income attributable to WESCO International by the weighted-average common shares and common share equivalents outstanding during the periods. The dilutive effect of common share equivalents is considered in the diluted earnings per share computation using the treasury stock method, which includes consideration of equity awards.

The following table sets forth the details of basic and diluted earnings per share:

	Three Months Ended				Nine Months Ended
	September 30				September 30
(In thousands, except per share data)	2018		2017		2018		2017
Net income attributable to WESCO International	$	66,849	$	53,675	$	169,210	$	140,918
Weighted-average common shares outstanding used in computing basic earnings per share	47,010		47,415		47,044		48,134
Common shares issuable upon exercise of dilutive equity awards	476		389		503		508
Weighted-average common shares outstanding and common share equivalents used in computing diluted earnings per share	47,486		47,804		47,547		48,642
Earnings per share attributable to WESCO International
Basic	$	1.42	$	1.13	$	3.60	$	2.93
Diluted	$	1.41	$	1.12	$	3.56	$	2.90

For the three and nine months ended September 30, 2018 the computation of diluted earnings per share attributable to WESCO International excluded stock-based awards of approximately 1.7 million and 1.5 million, respectively. For the three and nine months ended September 30, 2017, the computation of diluted earnings per share attributable to WESCO International excluded stock-based awards of approximately 1.5 million and 1.3 million, respectively. These amounts were excluded because their effect would have been antidilutive.

In December 2014, the Company's Board of Directors authorized the repurchase of up to $300 million of the Company's common stock through December 31, 2017 (the "2014 Repurchase Authorization"). During the nine months ended September 30, 2017, the Company repurchased 1,778,537 shares under the 2014 Repurchase Authorization for $100.0 million.

In December 2017, the Company's Board of Directors authorized the repurchase of up to $300 million of the Company's common stock through December 31, 2020 (the "2017 Repurchase Authorization"). On September 6, 2018, the Company entered into an accelerated stock repurchase agreement (the "ASR Transaction") with a financial institution to repurchase additional shares of its common stock pursuant to its 2017 Repurchase Authorization. In exchange for an up-front cash payment of $25.0 million, the Company received an initial share delivery of 351,821 shares. As of September 30, 2018, the ASR Transaction had not yet settled between the counterparties. The total number of shares ultimately delivered under the ASR Transaction will be determined by the average of the volume-weighted average prices of the Company's common stock for each exchange business day during the settlement valuation period. For purposes of computing earnings per share for the three and nine months ended September 30, 2018 and 2017, share repurchases were reflected as a reduction to common shares outstanding on the respective delivery dates. WESCO funded the repurchase with available cash and borrowings under the Company's accounts receivable securitization facility.

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EMPLOYEE BENEFIT PLANS

9 Months Ended

Sep. 30, 2018

Retirement Benefits [Abstract]

EMPLOYEE BENEFIT PLANS

8. EMPLOYEE BENEFIT PLANS

A majority of WESCO’s employees are covered by defined contribution retirement savings plans for their services rendered subsequent to WESCO’s formation. WESCO also offers a deferred compensation plan for select individuals. For U.S. participants, WESCO matches contributions made by employees at an amount equal to 50% of participants' total monthly contributions up to a maximum of 6% of eligible compensation. For Canadian participants, WESCO makes contributions in amounts ranging from 3% to 5% of participants' eligible compensation based on years of continuous service. WESCO may also make, subject to the Board of Directors' approval, a discretionary contribution to the defined contribution retirement savings plan covering U.S. participants if certain predetermined profit levels are attained. For the nine months ended September 30, 2018 and 2017, WESCO incurred charges of $33.5 million and $20.3 million, respectively, for all such plans. Contributions are made in cash to employee retirement savings plan accounts. The deferred compensation plan is an unfunded plan. As of September 30, 2018 and December 31, 2017, the Company's obligation under the deferred compensation plan was $23.8 million and $24.3 million, respectively. Employees have the option to transfer balances allocated to their accounts in the defined contribution retirement savings plan and the deferred compensation plan into any of the available investment options.

The Company sponsors a contributory defined benefit plan covering substantially all Canadian employees of EECOL and a Supplemental Executive Retirement Plan (the "SERP") for certain executives of EECOL. During the three and nine months ended September 30, 2018, the Company contributed $0.1 million and $0.3 million, respectively, to the SERP.

The following table sets forth the components of net periodic benefit costs for the defined benefit plans:

	Three Months Ended						Nine Months Ended
	September 30						September 30
(In thousands)	2018			2017			2018			2017
Service cost	$	1,296		$	1,118		$	3,955		$	3,234
Interest cost	1,026			1,007			3,131			2,915
Expected return on plan assets	(1,482		)	(1,432		)	(4,522		)	(4,144		)
Recognized actuarial gain	(11		)	(51		)	(35		)	(149		)
Net periodic benefit cost	$	829		$	642		$	2,529		$	1,856

In accordance with ASU 2017-07, as described in Note 2, the service cost of $1.3 million and $4.0 million for the three and nine months ended September 30, 2018, respectively, was reported as a component of selling, general and administrative expenses. The other components of net periodic benefit cost totaling a net benefit of $0.5 million and $1.4 million for the three and nine months ended September 30, 2018, respectively, were presented as a component of net interest and other, as described in Note 9 below. For the three and nine months ended September 30, 2017, the Company reclassified a net benefit of $0.5 million and $1.4 million, respectively, from selling, general and administrative expenses to net interest and other. The Company used the amounts disclosed in Note 7 of the Notes to Condensed Consolidated Financial Statements in the Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2017 as the estimation basis for applying the retrospective presentation requirements.

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COMMITMENTS AND CONTINGENCIES

9 Months Ended

Sep. 30, 2018

Commitments and Contingencies Disclosure [Abstract]

COMMITMENTS AND CONTINGENCIES

10. COMMITMENTS AND CONTINGENCIES

From time to time, a number of lawsuits and claims have been or may be asserted against us relating to the conduct of our business, including routine litigation relating to commercial and employment matters. The outcome of any litigation cannot be predicted with certainty, and some lawsuits may be determined adversely to us. However, management does not believe that the ultimate outcome of any such pending matters is likely to have a material adverse effect on our financial condition or liquidity, although the resolution in any fiscal period of one or more of these matters may have a material adverse effect on our results of operations for that period.

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INCOME TAXES

9 Months Ended

Sep. 30, 2018

Income Tax Disclosure [Abstract]

INCOME TAXES

11. INCOME TAXES

The effective tax rate for the three and nine months ended September 30, 2018 was 17.2% and 19.3%, respectively. The effective tax rate for the three and nine months ended September 30, 2017 was 25.5% and 25.3%, respectively. WESCO’s effective tax rate is typically impacted by the tax effect of intercompany financing, foreign tax rate differences, other nondeductible expenses and state income taxes. The effective tax rates for the current year periods are lower than the prior year periods primarily due to the Tax Cuts and Jobs Act of 2017 (the "TCJA"), which permanently reduced the U.S. federal statutory income tax rate from 35% to 21%, effective January 1, 2018. Also, the discrete benefits resulting from audit settlements favorably impacted the effective tax rate for the three months ended September 30, 2018.

The unaudited condensed consolidated financial information presented herein reflects provisional amounts for certain income tax effects of the TCJA for which the accounting is incomplete, but a reasonable estimate can be determined, based on enacted tax laws and rates as of September 30, 2018. Since the enactment of the TCJA on December 22, 2017, the Internal Revenue Service has issued proposed regulations and guidance regarding Section 965 of the Internal Revenue Code, as amended by the TCJA. We have reviewed the proposed regulations and guidance, and they do not materially impact the provisional amounts previously recorded for the one-time tax on the deemed repatriation of undistributed foreign earnings. Future adjustments (if any) resulting from additional regulatory guidance will be recognized as discrete income tax expense or benefit in the period the adjustments are determined.

The total amount of unrecognized tax benefits was reduced from $4.3 million to $1.6 million during the nine months ended September 30, 2018 due to audit settlements. The $1.6 million could affect the effective tax rate if recognized in the consolidated financial statements. It is reasonably possible that this amount will decrease by approximately $0.2 million within the next twelve months due to the expiration of statutes of limitation and the settlement of state audits.

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OTHER FINANCIAL INFORMATION

9 Months Ended

Sep. 30, 2018

Condensed Financial Information [Abstract]

OTHER FINANCIAL INFORMATION

12. CONDENSED CONSOLIDATING FINANCIAL INFORMATION

WESCO Distribution has outstanding $500 million in aggregate principal amount of 5.375% Senior Notes due 2021 (the "2021 Notes") and $350 million in aggregate principal amount of 5.375% Senior Notes due 2024 (the "2024 Notes"). The 2021 Notes and 2024 Notes are unsecured senior obligations of WESCO Distribution and are fully and unconditionally guaranteed on a senior unsecured basis by WESCO International.

Condensed consolidating financial information for WESCO International, WESCO Distribution and the non-guarantor subsidiaries is presented in the following tables.

	Condensed Consolidating Balance Sheet
	September 30, 2018
(In thousands)	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Cash and cash equivalents	$	—	$	57,052	$	85,708		$	—		$	142,760
Trade accounts receivable, net	—		—		1,265,880			—			1,265,880
Inventories	—		411,252		515,516			—			926,768
Prepaid expenses and other current assets	4,943		42,568		132,620			(9,040		)	171,091
Total current assets	4,943		510,872		1,999,724			(9,040		)	2,506,499
Intercompany receivables, net	—		—		2,270,584			(2,270,584		)	—
Property, buildings and equipment, net	—		56,351		100,778			—			157,129
Intangible assets, net	—		2,291		331,735			—			334,026
Goodwill	—		257,623		1,497,669			—			1,755,292
Investments in affiliates	3,188,872		5,144,891		—			(8,333,763		)	—
Other assets	—		2,780		23,065			—			25,845
Total assets	$	3,193,815	$	5,974,808	$	6,223,555		$	(10,613,387	)	$	4,778,791
Accounts payable	$	—	$	412,989	$	400,406		$	—		$	813,395
Short-term debt	—		—		31,125			—			31,125
Other current liabilities	—		72,762		143,286			(9,040		)	207,008
Total current liabilities	—		485,751		574,817			(9,040		)	1,051,528
Intercompany payables, net	952,642		1,317,942		—			(2,270,584		)	—
Long-term debt, net	—		864,779		364,535			—			1,229,314
Other noncurrent liabilities	3,820		117,464		144,828			—			266,112
Total WESCO International stockholders' equity	2,237,353		3,188,872		5,144,891			(8,333,763		)	2,237,353
Noncontrolling interests	—		—		(5,516		)	—			(5,516		)
Total liabilities and stockholders’ equity	$	3,193,815	$	5,974,808	$	6,223,555		$	(10,613,387	)	$	4,778,791

	Condensed Consolidating Balance Sheet
	December 31, 2017
(In thousands)	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Cash and cash equivalents	$	—	$	50,602	$	67,351		$	—		$	117,953
Trade accounts receivable, net	—		—		1,170,080			—			1,170,080
Inventories	—		430,092		526,056			—			956,148
Prepaid expenses and other current assets	4,730		42,547		152,531			(35,140		)	164,668
Total current assets	4,730		523,241		1,916,018			(35,140		)	2,408,849
Intercompany receivables, net	—		—		2,189,136			(2,189,136		)	—
Property, buildings and equipment, net	—		50,198		106,247			—			156,445
Intangible assets, net	—		2,770		364,334			—			367,104
Goodwill	—		257,623		1,514,254			—			1,771,877
Investments in affiliates	3,058,613		5,023,826		—			(8,082,439		)	—
Other assets	—		2,778		28,415			—			31,193
Total assets	$	3,063,343	$	5,860,436	$	6,118,404		$	(10,306,715	)	$	4,735,468
Accounts payable	$	—	$	417,690	$	381,830		$	—		$	799,520
Short-term debt	—		—		34,075			—			34,075
Other current liabilities	—		80,039		162,475			(35,140		)	207,374
Total current liabilities	—		497,729		578,380			(35,140		)	1,040,969
Intercompany payables, net	939,784		1,249,352		—			(2,189,136		)	—
Long-term debt, net	—		934,033		379,228			—			1,313,261
Other noncurrent liabilities	3,820		120,709		140,566			—			265,095
Total WESCO International stockholders' equity	2,119,739		3,058,613		5,023,826			(8,082,439		)	2,119,739
Noncontrolling interests	—		—		(3,596		)	—			(3,596		)
Total liabilities and stockholders’ equity	$	3,063,343	$	5,860,436	$	6,118,404		$	(10,306,715	)	$	4,735,468

	Condensed Consolidating Statement of Income and Comprehensive Income
	Three Months Ended
	September 30, 2018
(In thousands)	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—	$	899,994	$	1,206,174		$	(38,923	)	$	2,067,245
Cost of goods sold (excluding depreciation and
amortization)	—		727,052		981,908			(38,923		)	1,670,037
Selling, general and administrative expenses	—		149,390		134,683			—			284,073
Depreciation and amortization	—		4,475		11,143			—			15,618
Results of affiliates’ operations	66,645		61,771		—			(128,416		)	—
Net interest and other	—		13,127		3,923			—			17,050
Income tax expense	—		1,076		12,746			—			13,822
Net income	66,645		66,645		61,771			(128,416		)	66,645
Net loss attributable to noncontrolling interests	—		—		(204		)	—			(204		)
Net income attributable to WESCO International	$	66,645	$	66,645	$	61,975		$	(128,416	)	$	66,849
Other comprehensive income:
Foreign currency translation adjustments	20,486		20,486		20,486			(40,972		)	20,486
Comprehensive income attributable to WESCO International	$	87,131	$	87,131	$	82,461		$	(169,388	)	$	87,335

	Condensed Consolidating Statement of Income and Comprehensive Income
	Nine Months Ended
	September 30, 2018
(In thousands)	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—		$	2,703,468		$	3,578,653		$	(116,967	)	$	6,165,154
Cost of goods sold (excluding depreciation and
amortization)	—			2,189,683			2,915,387			(116,967		)	4,988,103
Selling, general and administrative expenses	—			447,437			420,353			—			867,790
Depreciation and amortization	—			13,749			33,572			—			47,321
Results of affiliates’ operations	167,289			158,093			—			(325,382		)	—
Net interest and other	—			41,202			13,372			—			54,574
Income tax expense	—			2,201			37,876			—			40,077
Net income	167,289			167,289			158,093			(325,382		)	167,289
Net loss attributable to noncontrolling interests	—			—			(1,921		)	—			(1,921		)
Net income attributable to WESCO International	$	167,289		$	167,289		$	160,014		$	(325,382	)	$	169,210
Other comprehensive loss:
Foreign currency translation adjustments	(37,029		)	(37,029		)	(37,029		)	74,058			(37,029		)
Comprehensive income attributable to WESCO International	$	130,260		$	130,260		$	122,985		$	(251,324	)	$	132,181

	Condensed Consolidating Statement of Income and Comprehensive Income
	Three Months Ended
	September 30, 2017
(In thousands)	WESCO International, Inc.		WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—	$	867,973		$	1,169,377		$	(37,191	)	$	2,000,159
Cost of goods sold (excluding depreciation and
amortization)	—		697,896			954,109			(37,191		)	1,614,814
Selling, general and administrative expenses	—		140,638			139,859			—			280,497
Depreciation and amortization	—		4,475			11,599			—			16,074
Results of affiliates’ operations	53,576		42,726			—			(96,302		)	—
Net interest and other	—		25,436			(8,601		)	—			16,835
Income tax (benefit) expense	—		(136		)	18,499			—			18,363
Net income	53,576		42,390			53,912			(96,302		)	53,576
Net loss attributable to noncontrolling interests	—		—			(99		)	—			(99		)
Net income attributable to WESCO International	$	53,576	$	42,390		$	54,011		$	(96,302	)	$	53,675
Other comprehensive income:
Foreign currency translation adjustments	51,148		51,148			51,148			(102,296		)	51,148
Comprehensive income attributable to WESCO International	$	104,724	$	93,538		$	105,159		$	(198,598	)	$	104,823

Reclassification

As described in Note 8, the Company reclassified a net benefit of $0.5 million from selling, general and administrative expenses to net interest and other in the previously reported Condensed Consolidated Statement of Income and Comprehensive Income of the non-guarantor subsidiaries for the three months ended September 30, 2017.

	Condensed Consolidating Statement of Income and Comprehensive Income
	Nine Months Ended
	September 30, 2017
(In thousands)	WESCO International, Inc.		WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—	$	2,490,102		$	3,289,693		$	(97,420	)	$	5,682,375
Cost of goods sold (excluding depreciation and
amortization)	—		2,002,708			2,675,608			(97,420		)	4,580,896
Selling, general and administrative expenses	—		410,624			405,029			—			815,653
Depreciation and amortization	—		13,811			33,947			—			47,758
Results of affiliates’ operations	140,915		117,907			—			(258,822		)	—
Net interest and other	—		74,961			(25,492		)	—			49,469
Income tax (benefit) expense	—		(3,034		)	50,718			—			47,684
Net income	140,915		108,939			149,883			(258,822		)	140,915
Net loss attributable to noncontrolling interests	—		—			(3		)	—			(3		)
Net income attributable to WESCO International	$	140,915	$	108,939		$	149,886		$	(258,822	)	$	140,918
Other comprehensive income:
Foreign currency translation adjustments	96,097		96,097			96,097			(192,194		)	96,097
Post retirement benefit plan adjustments, net of tax	252		252			252			(504		)	252
Comprehensive income attributable to WESCO International	$	237,264	$	205,288		$	246,235		$	(451,520	)	$	237,267

Reclassification

As described in Note 8, the Company reclassified a net benefit of $1.4 million from selling, general and administrative expenses to net interest and other in the previously reported Condensed Consolidated Statement of Income and Comprehensive Income of the non-guarantor subsidiaries for the nine months ended September 30, 2017.

	Condensed Consolidating Statement of Cash Flows
	Nine Months Ended
	September 30, 2018
(In thousands)	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net cash provided by operating activities	$	14,198		$	62,439		$	97,823		$	—		$	174,460
Investing activities:
Capital expenditures	—			(12,831		)	(10,918		)	—			(23,749		)
Dividends received from subsidiaries	—			118,271			—			(118,271		)	—
Other	—			(81,128		)	3,609			81,128			3,609
Net cash provided by (used in) investing activities	—			24,312			(7,309		)	(37,143		)	(20,140		)
Financing activities:
Borrowings	12,857			246,323			933,046			(81,128		)	1,111,098
Repayments	—			(318,323		)	(882,239		)	—			(1,200,562		)
Repurchases of common stock	(27,055		)	—			—			—			(27,055		)
Dividends paid by subsidiaries	—			—			(118,271		)	118,271			—
Other	—			(8,301		)	—			—			(8,301		)
Net cash used in financing activities	(14,198		)	(80,301		)	(67,464		)	37,143			(124,820		)
Effect of exchange rate changes on cash and cash equivalents	—			—			(4,693		)	—			(4,693		)
Net change in cash and cash equivalents	—			6,450			18,357			—			24,807
Cash and cash equivalents at the beginning of period	—			50,602			67,351			—			117,953
Cash and cash equivalents at the end of period	$	—		$	57,052		$	85,708		$	—		$	142,760

	Condensed Consolidating Statement of Cash Flows
	Nine Months Ended
	September 30, 2017
(In thousands)	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net cash (used in) provided by operating activities	$	(28,740	)	$	168,603		$	(58,752	)	$	—		$	81,111
Investing activities:
Capital expenditures	—			(7,435		)	(8,535		)	—			(15,970		)
Dividends received from subsidiaries	—			51,561			—			(51,561		)	—
Other	—			(174,032		)	16,711			160,811			3,490
Net cash (used in) provided by investing activities	—			(129,906		)	8,176			109,250			(12,480		)
Financing activities:
Borrowings	135,442			557,391			691,682			(173,907		)	1,210,608
Repayments	—			(587,485		)	(617,301		)	13,096			(1,191,690		)
Repurchases of common stock	(106,702		)	—			—			—			(106,702		)
Dividends paid by subsidiaries	—			—			(51,561		)	51,561			—
Other	—			(4,380		)	—			—			(4,380		)
Net cash provided by (used in) financing activities	28,740			(34,474		)	22,820			(109,250		)	(92,164		)
Effect of exchange rate changes on cash and cash equivalents	—			—			7,485			—			7,485
Net change in cash and cash equivalents	—			4,223			(20,271		)	—			(16,048		)
Cash and cash equivalents at the beginning of period	—			41,552			68,579			—			110,131
Cash and cash equivalents at the end of period	$	—		$	45,775		$	48,308		$	—		$	94,083

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Subsequent Events SUBSEQUENT EVENTS (Notes)

9 Months Ended

Sep. 30, 2018

Subsequent Events [Abstract]

Subsequent Events [Text Block]

13. SUBSEQUENT EVENTS

On October 31, 2018, the Company's Board of Directors approved an increase to the 2017 Repurchase Authorization from $300 million to $400 million, inclusive of the $25 million repurchase disclosed in Note 7 of these Notes to Condensed Consolidated Financial Statements.

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GOODWILL (Notes)

9 Months Ended

Sep. 30, 2018

Goodwill [Line Items]

Goodwill Disclosure [Text Block]

5. GOODWILL

The following table sets forth the changes in the carrying value of goodwill:

	Nine Months Ended
	September 30
(In thousands)	2018
Beginning balance January 1	$	1,771,877
Foreign currency exchange rate changes	(16,585		)
Ending balance September 30	$	1,755,292

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NET INTEREST AND OTHER (Notes)

9 Months Ended

Sep. 30, 2018

Other Income and Expenses [Abstract]

Other Nonoperating Income and Expense [Text Block]

9. NET INTEREST AND OTHER

Net interest and other includes interest expense, interest income, amortization of debt discount and debt issuance costs, the non-service cost components of net periodic benefit cost, and foreign exchange gains and losses from the remeasurement of certain financial instruments. For the three and nine months ended September 30, 2018, a foreign exchange gain of less than $0.1 million and a foreign exchange loss of $2.6 million, respectively, from the remeasurement of financial instruments were reported as a component of net interest and other. Foreign exchange gains and losses were not material for the three and nine months ended September 30, 2017.

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ACCOUNTING POLICIES (Policies)

9 Months Ended

Sep. 30, 2018

Accounting Policies [Abstract]

Basis of Presentation

Basis of Presentation

The accompanying unaudited Condensed Consolidated Financial Statements of WESCO have been prepared in accordance with Rule 10-01 of Regulation S-X of the Securities and Exchange Commission (the “SEC”). The unaudited condensed consolidated financial information should be read in conjunction with the audited Consolidated Financial Statements and Notes thereto included in WESCO’s 2017 Annual Report on Form 10-K as filed with the SEC on February 22, 2018. The Condensed Consolidated Balance Sheet at December 31, 2017 was derived from the audited Consolidated Financial Statements as of that date, but does not include all of the disclosures required by accounting principles generally accepted in the United States of America.

The unaudited Condensed Consolidated Balance Sheet as of September 30, 2018, the unaudited Condensed Consolidated Statements of Income and Comprehensive Income for the nine months ended September 30, 2018 and 2017, respectively, and the unaudited Condensed Consolidated Statements of Cash Flows for the nine months ended September 30, 2018 and 2017, respectively, in the opinion of management, have been prepared on the same basis as the audited Consolidated Financial Statements and include all adjustments necessary for the fair statement of the results of the interim periods presented herein. All adjustments reflected in the unaudited condensed consolidated financial information are of a normal recurring nature unless indicated. The results for the interim periods presented herein are not necessarily indicative of the results to be expected for the full year.

Reclassifications [Text Block]

Reclassifications

Effective January 1, 2018, WESCO adopted Accounting Standards Update (ASU) 2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The adoption of this ASU, as described below and in Note 8, resulted in the reclassification of amounts reported in the unaudited Condensed Consolidated Statements of Income and Comprehensive Income for the three and nine months ended September 30, 2017.

Fair Value of Financial Instruments

4. FAIR VALUE OF FINANCIAL INSTRUMENTS

The Company’s financial instruments consist of cash and cash equivalents, accounts receivable, accounts payable, bank overdrafts, and outstanding indebtedness. The reported carrying amounts of WESCO's financial instruments approximated their fair values as of September 30, 2018 and December 31, 2017.

The Company uses a market approach to determine the fair value of its debt instruments, utilizing quoted prices in active markets, interest rates and other relevant information generated by market transactions involving similar instruments. Therefore, the Company's debt instruments are classified as Level 2 within the fair value hierarchy.

New Accounting Pronouncements, Policy [Policy Text Block]

Recently Adopted Accounting Pronouncements

Effective January 1, 2018, WESCO adopted ASU 2014-09, Revenue from Contracts with Customers, and all the related amendments (“Topic 606”) using the modified retrospective approach to all open contracts. There was no impact to WESCO’s previously reported consolidated financial statements and WESCO does not expect the adoption of Topic 606 to have a material impact on its revenue and results of operations on an ongoing basis.

WESCO’s significant accounting policies are disclosed in Note 2 of the Notes to Consolidated Financial Statements in the Annual Report on Form 10-K for the year ended December 31, 2017. Changes to the Company’s significant accounting policies as a result of adopting Topic 606 are described in Note 3 below.

In August 2016, the Financial Accounting Standards Board (FASB) issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the Emerging Issues Task Force). This ASU provides guidance on eight specific cash flow issues where there is diversity in practice. The Company adopted this ASU in the first quarter of 2018. The adoption of this guidance did not have an impact on the unaudited condensed consolidated financial information presented herein.

In March 2017, the FASB issued ASU 2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. This ASU requires that an employer disaggregate the service cost from the other components of net benefit cost. The Company adopted this guidance on a retrospective basis in the first quarter of 2018. See Note 8 for a description of the impact of this accounting standard on the unaudited Condensed Consolidated Statements of Income and Comprehensive Income presented herein. The adoption of this guidance did not have an impact on the Company's unaudited Condensed Consolidated Balance Sheets and the unaudited Condensed Consolidated Statements of Cash Flows presented herein.

In May 2017, the FASB issued ASU 2017-09, Compensation—Stock Compensation (Topic 718): Scope of Modification Accounting. This ASU clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions, or the classification of the award (as equity or liability) changes as a result of the change in terms or conditions. The Company adopted this ASU in the first quarter of 2018. The adoption of this guidance did not have an impact on the unaudited condensed consolidated financial information presented herein.

Recently Issued Accounting Pronouncements

In February 2016, the FASB issued ASU 2016-02, Leases, a comprehensive new standard that amends various aspects of existing accounting guidance for leases, including the recognition of a right-of-use asset and a lease liability in the balance sheet and disclosing key information about leasing arrangements. This ASU is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. During 2018, the FASB issued additional ASUs that address implementation issues and correct or improve certain aspects of the new accounting guidance for leases, including ASU 2018-10, Codification Improvements to Topic 842, Leases and ASU 2018-11, Leases (Topic 842): Targeted Improvements. These ASUs do not change the core principles in the leasing standard outlined above. The amendments in ASU 2018-11 provide an optional transition method that allows entities to initially apply the new leases standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. Consequently, an entity’s reporting for the comparative periods will continue to be in accordance with current lease accounting guidance. Management established a cross-functional team to evaluate and implement the new standard. The team selected a third-party software solution to facilitate the accounting and financial reporting requirements of the new lease standard. Lease data elements have been gathered and are currently being migrated to the software solution. The new standard will be adopted in the first quarter of 2019 and the Company expects to use the optional transition method. While the Company has not yet completed its evaluation of the effects of adopting this ASU, right-of-use assets and lease liabilities will be recorded in the Consolidated Balance Sheets as of the effective date and thereafter.

In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which introduces new guidance for the accounting for credit losses on certain financial instruments. The amendments in this ASU are effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted. Management does not expect the adoption of this accounting standard to have a material impact on its consolidated financial statements and notes thereto.

In January 2017, the FASB issued ASU 2017-04, Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment, which eliminates Step 2 of the goodwill impairment test. Under the amendments in this ASU, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. An entity should apply the amendments in this ASU on a prospective basis. This guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Management expects to adopt this ASU in the fourth quarter of 2018 when the Company performs its annual impairment testing. The Company does not expect the adoption of this accounting standard to have a material impact on its consolidated financial statements and notes thereto.

In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement, which amends the disclosure requirements for recurring and nonrecurring fair value measurements by removing, modifying and adding certain disclosures. The amendments in this ASU are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted. Management does not expect the adoption of this accounting standard to have a material impact on its consolidated financial statements and notes thereto.

In August 2018, the FASB issued ASU 2018-14, Compensation—Retirement Benefits—Defined Benefit Plans—General (Subtopic 715-20): Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans, which amends the disclosure requirements for all employers that sponsor defined benefit pension and other post retirement plans by removing and adding certain disclosures. The amendments in this ASU are effective for fiscal years ending after December 15, 2020. Early adoption is permitted. Management does not expect the adoption of this accounting standard to have a material impact on its consolidated financial statements and notes thereto.

Other pronouncements issued by the FASB or other authoritative accounting standards groups with future effective dates are either not applicable or are not expected to be significant to WESCO’s financial position, results of operations or cash flows.

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STOCK-BASED COMPENSATION (Tables)

9 Months Ended

Sep. 30, 2018

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

During the three and nine months ended September 30, 2018 and 2017, WESCO granted the following stock-settled stock appreciation rights, restricted stock units and performance-based awards at the following weighted-average fair values:

	Three Months Ended				Nine Months Ended
	September 30, 2018		September 30, 2017		September 30, 2018		September 30, 2017
Stock-settled stock appreciation rights granted	9,415		12,076		509,046		455,807
Weighted-average fair value	$	17.40	$	15.74	$	18.38	$	20.52
Restricted stock units granted	2,686		2,313		119,457		100,993
Weighted-average fair value	$	61.41	$	57.30	$	62.72	$	71.33
Performance-based awards granted	—		—		44,144		39,978
Weighted-average fair value	$	—	$	—	$	62.80	$	76.63

Schedule of Share-based Compensation, Stock Options and Stock Appreciation Rights Award Activity [Table Text Block]

The following table sets forth a summary of stock-settled stock appreciation rights and related information for the nine months ended September 30, 2018:

	Awards		Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (In years)	Aggregate Intrinsic Value (In thousands)
Outstanding at December 31, 2017	2,238,607		$	57.75
Granted	509,046		62.68
Exercised	(186,662	)	40.73
Forfeited	(168,824	)	69.12
Outstanding at September 30, 2018	2,392,167		59.32		6.3	$	16,779
Exercisable at September 30, 2018	1,476,763		$	58.03	4.9	$	13,566

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]

The following table sets forth a summary of time-based restricted stock units and related information for the nine months ended September 30, 2018:

	Awards		Weighted- Average Fair Value
Unvested at December 31, 2017	290,054		$	58.11
Granted	119,457		62.72
Vested	(59,905	)	68.78
Forfeited	(14,539	)	57.09
Unvested at September 30, 2018	335,067		$	57.89

Schedule of Nonvested Performance-based Units Activity [Table Text Block]

The following table sets forth a summary of performance-based awards for the nine months ended September 30, 2018:

	Awards		Weighted- Average Fair Value
Unvested at December 31, 2017	148,508		$	60.23
Granted	44,144		62.80
Vested	—		—
Forfeited	(52,342	)	65.15
Unvested at September 30, 2018	140,310		$	59.20

Stock Appreciation Rights (SARs) [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

The fair value of stock-settled stock appreciation rights was estimated using the following weighted-average assumptions:

	Three Months Ended				Nine Months Ended
	September 30, 2018		September 30, 2017		September 30, 2018		September 30, 2017
Risk free interest rate	2.8	%	1.8	%	2.5	%	1.9	%
Expected life (in years)	5		5		5		5
Expected volatility	28	%	28	%	28	%	29	%

Performance Shares [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

The fair value of the performance shares granted during the nine months ended September 30, 2018 and 2017 was estimated using the following weighted-average assumptions:

	Nine Months Ended
	September 30, 2018		September 30, 2017
Grant date share price	$	62.80	$	71.65
WESCO expected volatility	n/a		29		%
Peer group median volatility	n/a		24		%
Risk-free interest rate	n/a		1.5		%
Correlation of peer company returns	n/a		114		%

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EARNINGS PER SHARE (Tables)

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

The following table sets forth the details of basic and diluted earnings per share:

	Three Months Ended				Nine Months Ended
	September 30				September 30
(In thousands, except per share data)	2018		2017		2018		2017
Net income attributable to WESCO International	$	66,849	$	53,675	$	169,210	$	140,918
Weighted-average common shares outstanding used in computing basic earnings per share	47,010		47,415		47,044		48,134
Common shares issuable upon exercise of dilutive equity awards	476		389		503		508
Weighted-average common shares outstanding and common share equivalents used in computing diluted earnings per share	47,486		47,804		47,547		48,642
Earnings per share attributable to WESCO International
Basic	$	1.42	$	1.13	$	3.60	$	2.93
Diluted	$	1.41	$	1.12	$	3.56	$	2.90

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EMPLOYEE BENEFIT PLANS Schedule of Net Benefit Costs (Tables)

9 Months Ended

Sep. 30, 2018

Postemployment Benefits [Abstract]

Schedule of Net Benefit Costs [Table Text Block]

The following table sets forth the components of net periodic benefit costs for the defined benefit plans:

	Three Months Ended						Nine Months Ended
	September 30						September 30
(In thousands)	2018			2017			2018			2017
Service cost	$	1,296		$	1,118		$	3,955		$	3,234
Interest cost	1,026			1,007			3,131			2,915
Expected return on plan assets	(1,482		)	(1,432		)	(4,522		)	(4,144		)
Recognized actuarial gain	(11		)	(51		)	(35		)	(149		)
Net periodic benefit cost	$	829		$	642		$	2,529		$	1,856

XML

OTHER FINANCIAL INFORMATION (Tables)

9 Months Ended

Sep. 30, 2018

Condensed Balance Sheet Statements, Captions [Line Items]

Condensed Balance Sheet [Table Text Block]

	Condensed Consolidating Balance Sheet
	September 30, 2018
(In thousands)	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Cash and cash equivalents	$	—	$	57,052	$	85,708		$	—		$	142,760
Trade accounts receivable, net	—		—		1,265,880			—			1,265,880
Inventories	—		411,252		515,516			—			926,768
Prepaid expenses and other current assets	4,943		42,568		132,620			(9,040		)	171,091
Total current assets	4,943		510,872		1,999,724			(9,040		)	2,506,499
Intercompany receivables, net	—		—		2,270,584			(2,270,584		)	—
Property, buildings and equipment, net	—		56,351		100,778			—			157,129
Intangible assets, net	—		2,291		331,735			—			334,026
Goodwill	—		257,623		1,497,669			—			1,755,292
Investments in affiliates	3,188,872		5,144,891		—			(8,333,763		)	—
Other assets	—		2,780		23,065			—			25,845
Total assets	$	3,193,815	$	5,974,808	$	6,223,555		$	(10,613,387	)	$	4,778,791
Accounts payable	$	—	$	412,989	$	400,406		$	—		$	813,395
Short-term debt	—		—		31,125			—			31,125
Other current liabilities	—		72,762		143,286			(9,040		)	207,008
Total current liabilities	—		485,751		574,817			(9,040		)	1,051,528
Intercompany payables, net	952,642		1,317,942		—			(2,270,584		)	—
Long-term debt, net	—		864,779		364,535			—			1,229,314
Other noncurrent liabilities	3,820		117,464		144,828			—			266,112
Total WESCO International stockholders' equity	2,237,353		3,188,872		5,144,891			(8,333,763		)	2,237,353
Noncontrolling interests	—		—		(5,516		)	—			(5,516		)
Total liabilities and stockholders’ equity	$	3,193,815	$	5,974,808	$	6,223,555		$	(10,613,387	)	$	4,778,791

	Condensed Consolidating Balance Sheet
	December 31, 2017
(In thousands)	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Cash and cash equivalents	$	—	$	50,602	$	67,351		$	—		$	117,953
Trade accounts receivable, net	—		—		1,170,080			—			1,170,080
Inventories	—		430,092		526,056			—			956,148
Prepaid expenses and other current assets	4,730		42,547		152,531			(35,140		)	164,668
Total current assets	4,730		523,241		1,916,018			(35,140		)	2,408,849
Intercompany receivables, net	—		—		2,189,136			(2,189,136		)	—
Property, buildings and equipment, net	—		50,198		106,247			—			156,445
Intangible assets, net	—		2,770		364,334			—			367,104
Goodwill	—		257,623		1,514,254			—			1,771,877
Investments in affiliates	3,058,613		5,023,826		—			(8,082,439		)	—
Other assets	—		2,778		28,415			—			31,193
Total assets	$	3,063,343	$	5,860,436	$	6,118,404		$	(10,306,715	)	$	4,735,468
Accounts payable	$	—	$	417,690	$	381,830		$	—		$	799,520
Short-term debt	—		—		34,075			—			34,075
Other current liabilities	—		80,039		162,475			(35,140		)	207,374
Total current liabilities	—		497,729		578,380			(35,140		)	1,040,969
Intercompany payables, net	939,784		1,249,352		—			(2,189,136		)	—
Long-term debt, net	—		934,033		379,228			—			1,313,261
Other noncurrent liabilities	3,820		120,709		140,566			—			265,095
Total WESCO International stockholders' equity	2,119,739		3,058,613		5,023,826			(8,082,439		)	2,119,739
Noncontrolling interests	—		—		(3,596		)	—			(3,596		)
Total liabilities and stockholders’ equity	$	3,063,343	$	5,860,436	$	6,118,404		$	(10,306,715	)	$	4,735,468

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OTHER FINANCIAL INFORMATION Condensed Income Statement (Tables)

9 Months Ended

Sep. 30, 2018

Condensed Income Statements, Captions [Line Items]

Condensed Income Statement [Table Text Block]

	Condensed Consolidating Statement of Income and Comprehensive Income
	Three Months Ended
	September 30, 2017
(In thousands)	WESCO International, Inc.		WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—	$	867,973		$	1,169,377		$	(37,191	)	$	2,000,159
Cost of goods sold (excluding depreciation and
amortization)	—		697,896			954,109			(37,191		)	1,614,814
Selling, general and administrative expenses	—		140,638			139,859			—			280,497
Depreciation and amortization	—		4,475			11,599			—			16,074
Results of affiliates’ operations	53,576		42,726			—			(96,302		)	—
Net interest and other	—		25,436			(8,601		)	—			16,835
Income tax (benefit) expense	—		(136		)	18,499			—			18,363
Net income	53,576		42,390			53,912			(96,302		)	53,576
Net loss attributable to noncontrolling interests	—		—			(99		)	—			(99		)
Net income attributable to WESCO International	$	53,576	$	42,390		$	54,011		$	(96,302	)	$	53,675
Other comprehensive income:
Foreign currency translation adjustments	51,148		51,148			51,148			(102,296		)	51,148
Comprehensive income attributable to WESCO International	$	104,724	$	93,538		$	105,159		$	(198,598	)	$	104,823

	Condensed Consolidating Statement of Income and Comprehensive Income
	Nine Months Ended
	September 30, 2017
(In thousands)	WESCO International, Inc.		WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—	$	2,490,102		$	3,289,693		$	(97,420	)	$	5,682,375
Cost of goods sold (excluding depreciation and
amortization)	—		2,002,708			2,675,608			(97,420		)	4,580,896
Selling, general and administrative expenses	—		410,624			405,029			—			815,653
Depreciation and amortization	—		13,811			33,947			—			47,758
Results of affiliates’ operations	140,915		117,907			—			(258,822		)	—
Net interest and other	—		74,961			(25,492		)	—			49,469
Income tax (benefit) expense	—		(3,034		)	50,718			—			47,684
Net income	140,915		108,939			149,883			(258,822		)	140,915
Net loss attributable to noncontrolling interests	—		—			(3		)	—			(3		)
Net income attributable to WESCO International	$	140,915	$	108,939		$	149,886		$	(258,822	)	$	140,918
Other comprehensive income:
Foreign currency translation adjustments	96,097		96,097			96,097			(192,194		)	96,097
Post retirement benefit plan adjustments, net of tax	252		252			252			(504		)	252
Comprehensive income attributable to WESCO International	$	237,264	$	205,288		$	246,235		$	(451,520	)	$	237,267

	Condensed Consolidating Statement of Income and Comprehensive Income
	Nine Months Ended
	September 30, 2018
(In thousands)	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—		$	2,703,468		$	3,578,653		$	(116,967	)	$	6,165,154
Cost of goods sold (excluding depreciation and
amortization)	—			2,189,683			2,915,387			(116,967		)	4,988,103
Selling, general and administrative expenses	—			447,437			420,353			—			867,790
Depreciation and amortization	—			13,749			33,572			—			47,321
Results of affiliates’ operations	167,289			158,093			—			(325,382		)	—
Net interest and other	—			41,202			13,372			—			54,574
Income tax expense	—			2,201			37,876			—			40,077
Net income	167,289			167,289			158,093			(325,382		)	167,289
Net loss attributable to noncontrolling interests	—			—			(1,921		)	—			(1,921		)
Net income attributable to WESCO International	$	167,289		$	167,289		$	160,014		$	(325,382	)	$	169,210
Other comprehensive loss:
Foreign currency translation adjustments	(37,029		)	(37,029		)	(37,029		)	74,058			(37,029		)
Comprehensive income attributable to WESCO International	$	130,260		$	130,260		$	122,985		$	(251,324	)	$	132,181

	Condensed Consolidating Statement of Income and Comprehensive Income
	Nine Months Ended
	September 30, 2018
(In thousands)	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—		$	2,703,468		$	3,578,653		$	(116,967	)	$	6,165,154
Cost of goods sold (excluding depreciation and
amortization)	—			2,189,683			2,915,387			(116,967		)	4,988,103
Selling, general and administrative expenses	—			447,437			420,353			—			867,790
Depreciation and amortization	—			13,749			33,572			—			47,321
Results of affiliates’ operations	167,289			158,093			—			(325,382		)	—
Net interest and other	—			41,202			13,372			—			54,574
Income tax expense	—			2,201			37,876			—			40,077
Net income	167,289			167,289			158,093			(325,382		)	167,289
Net loss attributable to noncontrolling interests	—			—			(1,921		)	—			(1,921		)
Net income attributable to WESCO International	$	167,289		$	167,289		$	160,014		$	(325,382	)	$	169,210
Other comprehensive loss:
Foreign currency translation adjustments	(37,029		)	(37,029		)	(37,029		)	74,058			(37,029		)
Comprehensive income attributable to WESCO International	$	130,260		$	130,260		$	122,985		$	(251,324	)	$	132,181

	Condensed Consolidating Statement of Income and Comprehensive Income
	Three Months Ended
	September 30, 2018
(In thousands)	WESCO International, Inc.		WESCO Distribution, Inc.		Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net sales	$	—	$	899,994	$	1,206,174		$	(38,923	)	$	2,067,245
Cost of goods sold (excluding depreciation and
amortization)	—		727,052		981,908			(38,923		)	1,670,037
Selling, general and administrative expenses	—		149,390		134,683			—			284,073
Depreciation and amortization	—		4,475		11,143			—			15,618
Results of affiliates’ operations	66,645		61,771		—			(128,416		)	—
Net interest and other	—		13,127		3,923			—			17,050
Income tax expense	—		1,076		12,746			—			13,822
Net income	66,645		66,645		61,771			(128,416		)	66,645
Net loss attributable to noncontrolling interests	—		—		(204		)	—			(204		)
Net income attributable to WESCO International	$	66,645	$	66,645	$	61,975		$	(128,416	)	$	66,849
Other comprehensive income:
Foreign currency translation adjustments	20,486		20,486		20,486			(40,972		)	20,486
Comprehensive income attributable to WESCO International	$	87,131	$	87,131	$	82,461		$	(169,388	)	$	87,335

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OTHER FINANCIAL INFORMATION Condensed Cash Flow Statement (Tables)

9 Months Ended

Sep. 30, 2018

Condensed Cash Flow Statements, Captions [Line Items]

Condensed Cash Flow Statement [Table Text Block]

	Condensed Consolidating Statement of Cash Flows
	Nine Months Ended
	September 30, 2017
(In thousands)	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net cash (used in) provided by operating activities	$	(28,740	)	$	168,603		$	(58,752	)	$	—		$	81,111
Investing activities:
Capital expenditures	—			(7,435		)	(8,535		)	—			(15,970		)
Dividends received from subsidiaries	—			51,561			—			(51,561		)	—
Other	—			(174,032		)	16,711			160,811			3,490
Net cash (used in) provided by investing activities	—			(129,906		)	8,176			109,250			(12,480		)
Financing activities:
Borrowings	135,442			557,391			691,682			(173,907		)	1,210,608
Repayments	—			(587,485		)	(617,301		)	13,096			(1,191,690		)
Repurchases of common stock	(106,702		)	—			—			—			(106,702		)
Dividends paid by subsidiaries	—			—			(51,561		)	51,561			—
Other	—			(4,380		)	—			—			(4,380		)
Net cash provided by (used in) financing activities	28,740			(34,474		)	22,820			(109,250		)	(92,164		)
Effect of exchange rate changes on cash and cash equivalents	—			—			7,485			—			7,485
Net change in cash and cash equivalents	—			4,223			(20,271		)	—			(16,048		)
Cash and cash equivalents at the beginning of period	—			41,552			68,579			—			110,131
Cash and cash equivalents at the end of period	$	—		$	45,775		$	48,308		$	—		$	94,083

	Condensed Consolidating Statement of Cash Flows
	Nine Months Ended
	September 30, 2018
(In thousands)	WESCO International, Inc.			WESCO Distribution, Inc.			Non-Guarantor Subsidiaries			Consolidating and Eliminating Entries			Consolidated
Net cash provided by operating activities	$	14,198		$	62,439		$	97,823		$	—		$	174,460
Investing activities:
Capital expenditures	—			(12,831		)	(10,918		)	—			(23,749		)
Dividends received from subsidiaries	—			118,271			—			(118,271		)	—
Other	—			(81,128		)	3,609			81,128			3,609
Net cash provided by (used in) investing activities	—			24,312			(7,309		)	(37,143		)	(20,140		)
Financing activities:
Borrowings	12,857			246,323			933,046			(81,128		)	1,111,098
Repayments	—			(318,323		)	(882,239		)	—			(1,200,562		)
Repurchases of common stock	(27,055		)	—			—			—			(27,055		)
Dividends paid by subsidiaries	—			—			(118,271		)	118,271			—
Other	—			(8,301		)	—			—			(8,301		)
Net cash used in financing activities	(14,198		)	(80,301		)	(67,464		)	37,143			(124,820		)
Effect of exchange rate changes on cash and cash equivalents	—			—			(4,693		)	—			(4,693		)
Net change in cash and cash equivalents	—			6,450			18,357			—			24,807
Cash and cash equivalents at the beginning of period	—			50,602			67,351			—			117,953
Cash and cash equivalents at the end of period	$	—		$	57,052		$	85,708		$	—		$	142,760

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GOODWILL (Tables)

9 Months Ended

Sep. 30, 2018

Goodwill [Line Items]

Schedule of Goodwill [Table Text Block]

	Nine Months Ended
	September 30
(In thousands)	2018
Beginning balance January 1	$	1,771,877
Foreign currency exchange rate changes	(16,585		)
Ending balance September 30	$	1,755,292

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REVENUE (Tables)

9 Months Ended

Sep. 30, 2018

Revenue from Contract with Customer [Abstract]

Disaggregation of Revenue [Table Text Block]

The following tables disaggregate WESCO’s revenue by end market and geography:

	Three Months Ended				Nine Months Ended
	September 30				September 30
(In thousands)	2018		2017		2018		2017
Industrial	$	723,869	$	722,227	$	2,243,590	$	2,111,813
Construction	686,165		674,996		2,007,708		1,870,406
Utility	345,937		312,501		998,438		861,162
Commercial, Institutional and Government ("CIG")	311,274		290,435		915,418		838,994
Total by end market	$	2,067,245	$	2,000,159	$	6,165,154	$	5,682,375

	Three Months Ended				Nine Months Ended
	September 30				September 30
(In thousands)	2018		2017		2018		2017
United States	$	1,525,393	$	1,473,016	$	4,571,533	$	4,267,684
Other (1)	541,852		527,143		1,593,621		1,414,691
Total by geography	$	2,067,245	$	2,000,159	$	6,165,154	$	5,682,375

⁽¹⁾  Other primarily includes net sales originating in Canada.

Revenue Recognition, Revenue Reductions [Policy Text Block]

WESCO’s revenues are adjusted for variable consideration, which includes customer volume rebates, returns, and discounts. WESCO measures variable consideration by estimating expected outcomes using analysis and inputs based upon anticipated performance, historical data, as well as current and forecasted information. Measurement and recognition of variable consideration is reviewed by management on a monthly basis and revenue is adjusted accordingly. Variable consideration reduced revenue for the three months ended September 30, 2018 and 2017 by approximately $25.1 million and $24.2 million, respectively, and by approximately $74.5 million and $66.5 million for the nine months ended September 30, 2018 and 2017, respectively.

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ORGANIZATION (Details)	Sep. 30, 2018 customers countries branches
Restructuring Cost and Reserve [Line Items]
Active customers (in customers) | customers	70,000
Full service branches (in branches) | branches	500
Additional countries (in countries) | countries	16

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ORGANIZATION Organization (Details)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Distribution Centers	10

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ACCOUNTING POLICIES (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Prepaid expenses and other current assets	$ 90,415	$ 63,439
Assets, Current	2,506,499	2,408,849
Goodwill	1,755,292	1,771,877
Liabilities and Equity	4,778,791	4,735,468
Other Accrued Liabilities, Current	102,489	95,820
Liabilities, Current	1,051,528	1,040,969
Assets	4,778,791	4,735,468
Deferred Tax Liabilities, Net, Noncurrent	147,048	136,858
Liabilities	2,546,954	2,619,325
Retained earnings	2,249,327	2,079,697
Accumulated other comprehensive income	(349,619)	(312,590)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 2,231,837	$ 2,116,143

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ACQUISITIONS - ACQUISITIONS (Details)	Sep. 30, 2018 branches
Business Acquisition [Line Items]
Number of Stores	500

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SCHEDULE OF SHARE-BASED COMPENSATION, STOCK OPTIONS AND STOCK APPRECIATION RIGHTS AWARD ACTIVITY (Details) - Stock Appreciation Rights (SARs) [Member] - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 62.68
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	$ 13,566		$ 13,566
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 59.32		$ 59.32		$ 57.75
Share-based Compensation Arrangement By Share-based Payment Award, Options and Stock Appreciation Rights, Outstanding [Roll Forward]
Beginning of Year (in shares)	1,476,763		1,476,763
Grants in Period (in shares)	9,415	12,076	509,046	455,807
Exercises in Period (in shares)			186,662
Forfeitures in Period (in shares)			168,824
Weighted Average Exercise Price, Exercises in Period (in dollars per share)			$ 40.73
Weighted Average Exercise Price, Forfeitures in Period (in dollars per share)			69.12
Weighted Average Exercise Price, Exercisable (in dollars per share)	$ 58.03		$ 58.03
Weighted Average Remaining Contractual Term, Outstanding (in years)			6 years 3 months
Weighted Average Remaining Contractual Term, Exercisable (in years)			4 years 11 months
Aggregate Intrinsic Value, Outstanding	$ 16,779		$ 16,779
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number	2,392,167		2,392,167		2,238,607

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SCHEDULE OF SHARE-BASED PAYMENT AWARD, VALUATION ASSUMPTIONS (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk free interest rate	2.80%	1.80%	2.50%	1.90%
Expected life (in years)	5 years	5 years	5 years	5 years
WESCO expected volatility	28.00%	28.00%	28.00%	29.00%
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	9,415	12,076	509,046	455,807
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 17.40	$ 15.74	$ 18.38	$ 20.52
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	2,686	2,313	119,457	100,993
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 61.41	$ 57.30	$ 62.72	$ 71.33
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	0	0	44,144	39,978
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 0.00	$ 0.00	$ 62.80	$ 76.63
Risk free interest rate				0.00%
WESCO expected volatility				0.00%

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SUMMARY OF RESTRICTED STOCK UNITS (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested (in shares)	335,067		335,067		290,054
Granted (in shares)	2,686	2,313	119,457	100,993
Vested (in shares)			(59,905)
Forfeited (in shares)			(14,539)
Unvested, Weighted Average Fair Value (in dollars per share)	$ 57.89		$ 57.89		$ 58.11
Granted, Weighted Average Fair Value (in dollars per share)	$ 61.41	$ 57.30	62.72	$ 71.33
Vested in Period, Weighted Average Fair Value (in dollars per share)			68.78
Forfeited in Period, Weighted Average Fair Value (in dollars per share)			$ 57.09

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SUMMARY OF PERFORMANCE-BASED AWARDS (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested (in shares)	140,310		140,310		148,508
Granted (in shares)	0	0	44,144	39,978
Vested (in shares)			0
Forfeited (in shares)			(52,342)
Unvested, Weighted Average Fair Value (in dollars per share)	$ 59.20		$ 59.20		$ 60.23
Granted, Weighted Average Fair Value (in dollars per share)	$ 0.00	$ 0.00	62.80	$ 76.63
Vested in Period, Weighted Average Fair Value (in dollars per share)			0.00
Forfeited in Period, Weighted Average Fair Value (in dollars per share)			$ 65.15
Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested (in shares)	91,505		91,505
Share-based Compensation Award, Tranche Two [Member] | Net Income Growth Rate [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested (in shares)	48,805		48,805
Share-based Compensation Award, Tranche Two [Member] | Earnings Per Share Growth [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested (in shares)	21,350		21,350
Share-based Compensation Award, Tranche Two [Member] | Return on Net Assets [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested (in shares)	21,350		21,350

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SCHEDULE OF SHARE-BASED PAYMENT AWARD, PERFORMANCE-BASED AWARDS, VALUATION ASSUMPTIONS (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
WESCO expected volatility	28.00%	28.00%	28.00%	29.00%
Risk free interest rate	2.80%	1.80%	2.50%	1.90%
Correlation				0.00%
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price	$ 62.80	$ 71.65	$ 62.80	$ 71.65
WESCO expected volatility				0.00%
Risk free interest rate				0.00%

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STOCK-BASED COMPENSATION (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended		12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 4.1	$ 3.5	$ 12.1	$ 11.3
Total unrecognized compensation cost		$ 22.9		$ 22.9
Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance-based awards outstanding (in shares)		48,805		48,805
Performance-based Awards - Peer Group Total Shareholder Return [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance-based awards outstanding (in shares)		91,505		91,505
Scenario, Forecast [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 4.1					$ 0.7	$ 6.3	$ 11.8

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SCHEDULE OF EARNINGS PER SHARE, BASIC AND DILUTED (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income (loss) attributable to WESCO International, Inc.	$ 66,849	$ 53,675	$ 169,210	$ 140,918
Weighted average common shares outstanding used in computing basic earnings per share (in shares)	47,010	47,415	47,044	48,134
Common shares issuable upon exercise of dilutive stock options (in shares)	476	389	503	508
Weighted average common shares outstanding and common share equivalents used in computing diluted earnings per share (in shares)	47,486	47,804	47,547	48,642
Earnings Per Share, Basic and Diluted [Abstract]
Basic (in dollars per share)	$ 1.42	$ 1.13	$ 3.60	$ 2.93
Diluted (in dollars per share)	$ 1.41	$ 1.12	$ 3.56	$ 2.90

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EARNINGS PER SHARE (Details) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Equity Award [Domain]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1.7	1.5	1.5	1.3

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EARNINGS PER SHARE Accelerated Share Repurchase (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Accelerated Share Repurchases [Line Items]
Payments for Repurchase of Common Stock	$ (27,055)	$ (106,702)
Stock Repurchase Program, Authorized Amount	$ 300,000
Treasury Stock, Shares, Acquired	351,821
Stock Repurchase Program Expiration Date	Dec. 31, 2020		Dec. 31, 2017
Treasury Stock, Common [Member]
Accelerated Share Repurchases [Line Items]
Payments for Repurchase of Common Stock	$ (25,000)	$ (100,000)
Treasury Stock, Shares, Acquired		1,778,537

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EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Retirement Benefits [Abstract]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 100		$ 300
Schedule of Employee Benefit Plans [Line Items]
Defined Benefit Plan, Service Cost	1,296	$ 1,118	3,955	$ 3,234
Postemployment Benefits, Period Expense			33,500	$ 20,300
Deferred Compensation Liability, Classified, Noncurrent	$ 23,800		$ 23,800		$ 24,300
CANADA | Minimum [Member]
Schedule of Employee Benefit Plans [Line Items]
Defined Contribution Plan Employer Matching Contribution Percent			3.00%
CANADA | Maximum [Member]
Schedule of Employee Benefit Plans [Line Items]
Defined Contribution Plan Employer Matching Contribution Percent			5.00%
UNITED STATES
Schedule of Employee Benefit Plans [Line Items]
Defined Contribution Plan, Employer Matching Contribution, Percent of Match			50.00%
Defined Contribution Plan Employer Matching Contribution Percent			6.00%

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EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS Pension Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 100		$ 300
Service cost	1,296	$ 1,118	3,955	$ 3,234
Interest cost	1,026	1,007	3,131	2,915
Expected return on plan assets	(1,482)	(1,432)	(4,522)	(4,144)
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	(11)	(51)	(35)	(149)
Net periodic benefit cost	829	642	2,529	1,856
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other Nonoperating Gains (Losses)	$ (500)	$ (500)	$ (1,400)	$ (1,400)

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INCOME TAXES (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Tax Contingency [Line Items]
Effective tax rate	17.20%	25.52579%	19.30%	25.28327%
Federal statutory rate			21.00%	35.00%
Unrecognized Tax Benefits	$ 1.6		$ 1.6		$ 4.3
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit	$ 0.2		$ 0.2

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INCOME TAXES Income Tax Rates (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Effective Income Tax Rate Reconciliation, Percent	17.20%	25.52579%	19.30%	25.28327%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			21.00%	35.00%

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OTHER FINANCIAL INFORMATION (Details) - Unsecured Debt [Member] $ in Millions	Sep. 30, 2018 USD ($)
2021 Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 500
2024 Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 350

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CONDENSED CONSOLIDATED BALANCE SHEETS (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Condensed Financial Information [Line Items]
Cash and cash equivalents	$ 142,760	$ 117,953	$ 94,083	$ 110,131
Trade accounts receivable, net	1,265,880	1,170,080
Inventories, net	926,768	956,148
Prepaid Expense and Other Assets, Current	90,415	63,439
Total current assets	2,506,499	2,408,849
Property, buildings and equipment, net	157,129	156,445
Intangible assets, net	334,026	367,104
Goodwill and other intangibles, net	1,755,292	1,771,877
Other assets	25,845	31,193
Total assets	4,778,791	4,735,468
Accounts payable	813,395	799,520
Short-term debt	31,125	34,075
Total current liabilities	1,051,528	1,040,969
Long-term Debt, Excluding Current Maturities	1,229,314	1,313,261
Total stockholders' equity	2,237,353	2,119,739
Stockholders' Equity Attributable to Noncontrolling Interest	5,516	3,596
Total liabilities and stockholders' equity	4,778,791	4,735,468
Parent Company [Member]
Condensed Financial Information [Line Items]
Cash and cash equivalents	0	0	0	0
Trade accounts receivable, net	0	0
Inventories, net	0	0
Prepaid Expense and Other Assets, Current	4,943	4,730
Total current assets	4,943	4,730
Intercompany receivables, net	0	0
Property, buildings and equipment, net	0	0
Intangible assets, net	0	0
Goodwill and other intangibles, net	0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	3,188,872	3,058,613
Other assets	0	0
Total assets	3,193,815	3,063,343
Accounts payable	0	0
Short-term debt	0	0
Other Liabilities, Current	0	0
Total current liabilities	0	0
Intercompany payables, net	952,642	939,784
Long-term Debt, Excluding Current Maturities	0	0
Liabilities, Other than Long-term Debt, Noncurrent	3,820	3,820
Total stockholders' equity	2,237,353	2,119,739
Stockholders' Equity Attributable to Noncontrolling Interest	0	0
Total liabilities and stockholders' equity	3,193,815	3,063,343
Guarantor Subsidiaries [Member]
Condensed Financial Information [Line Items]
Cash and cash equivalents	57,052	50,602	45,775	41,552
Trade accounts receivable, net	0	0
Inventories, net	411,252	430,092
Prepaid Expense and Other Assets, Current	42,568	42,547
Total current assets	510,872	523,241
Intercompany receivables, net	0	0
Property, buildings and equipment, net	56,351	50,198
Intangible assets, net	2,291	2,770
Goodwill and other intangibles, net	257,623	257,623
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	5,144,891	5,023,826
Other assets	2,780	2,778
Total assets	5,974,808	5,860,436
Accounts payable	412,989	417,690
Short-term debt	0	0
Other Liabilities, Current	72,762	80,039
Total current liabilities	485,751	497,729
Intercompany payables, net	1,317,942	1,249,352
Long-term Debt, Excluding Current Maturities	864,779	934,033
Liabilities, Other than Long-term Debt, Noncurrent	117,464	120,709
Total stockholders' equity	3,188,872	3,058,613
Stockholders' Equity Attributable to Noncontrolling Interest	0	0
Total liabilities and stockholders' equity	5,974,808	5,860,436
Non-Guarantor Subsidiaries [Member]
Condensed Financial Information [Line Items]
Cash and cash equivalents	85,708	67,351	48,308	68,579
Trade accounts receivable, net	1,265,880	1,170,080
Inventories, net	515,516	526,056
Prepaid Expense and Other Assets, Current	132,620	152,531
Total current assets	1,999,724	1,916,018
Intercompany receivables, net	2,270,584	2,189,136
Property, buildings and equipment, net	100,778	106,247
Intangible assets, net	331,735	364,334
Goodwill and other intangibles, net	1,497,669	1,514,254
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	0
Other assets	23,065	28,415
Total assets	6,223,555	6,118,404
Accounts payable	400,406	381,830
Short-term debt	31,125	34,075
Other Liabilities, Current	143,286	162,475
Total current liabilities	574,817	578,380
Intercompany payables, net	0	0
Long-term Debt, Excluding Current Maturities	364,535	379,228
Liabilities, Other than Long-term Debt, Noncurrent	144,828	140,566
Total stockholders' equity	5,144,891	5,023,826
Stockholders' Equity Attributable to Noncontrolling Interest	5,516	3,596
Total liabilities and stockholders' equity	6,223,555	6,118,404
Consolidated Entities [Member]
Condensed Financial Information [Line Items]
Cash and cash equivalents	142,760	117,953	94,083	110,131
Trade accounts receivable, net	1,265,880	1,170,080
Inventories, net	926,768	956,148
Prepaid Expense and Other Assets, Current	171,091	164,668
Total current assets	2,506,499	2,408,849
Intercompany receivables, net	0	0
Property, buildings and equipment, net	157,129	156,445
Intangible assets, net	334,026	367,104
Goodwill and other intangibles, net	1,755,292	1,771,877
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	0
Other assets	25,845	31,193
Total assets	4,778,791	4,735,468
Accounts payable	813,395	799,520
Short-term debt	31,125	34,075
Other Liabilities, Current	207,008	207,374
Total current liabilities	1,051,528	1,040,969
Intercompany payables, net	0	0
Long-term Debt, Excluding Current Maturities	1,229,314	1,313,261
Liabilities, Other than Long-term Debt, Noncurrent	266,112	265,095
Total stockholders' equity	2,237,353	2,119,739
Stockholders' Equity Attributable to Noncontrolling Interest	5,516	3,596
Total liabilities and stockholders' equity	4,778,791	4,735,468
Consolidation, Eliminations [Member]
Condensed Financial Information [Line Items]
Cash and cash equivalents	0	0	$ 0	$ 0
Trade accounts receivable, net	0	0
Inventories, net	0	0
Prepaid Expense and Other Assets, Current	(9,040)	(35,140)
Total current assets	(9,040)	(35,140)
Intercompany receivables, net	(2,270,584)	(2,189,136)
Property, buildings and equipment, net	0	0
Intangible assets, net	0	0
Goodwill and other intangibles, net	0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	(8,333,763)	(8,082,439)
Other assets	0	0
Total assets	(10,613,387)	(10,306,715)
Accounts payable	0	0
Short-term debt	0	0
Other Liabilities, Current	(9,040)	(35,140)
Total current liabilities	(9,040)	(35,140)
Intercompany payables, net	(2,270,584)	(2,189,136)
Long-term Debt, Excluding Current Maturities	0	0
Liabilities, Other than Long-term Debt, Noncurrent	0	0
Total stockholders' equity	(8,333,763)	(8,082,439)
Stockholders' Equity Attributable to Noncontrolling Interest	0	0
Total liabilities and stockholders' equity	$ (10,613,387)	$ (10,306,715)

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CONDENSED CONSOLIDATED INCOME STATEMENTS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Condensed Financial Information [Line Items]
Revenues	$ 2,067,245	$ 2,000,159	$ 6,165,154	$ 5,682,375
Cost of goods sold	1,670,037	1,614,814	4,988,103	4,580,896
Selling, general and administrative expense	284,073	280,497	867,790	815,653
Depreciation and amortization	15,618	16,074	47,321	47,758
Provision for income taxes	13,822	18,363	40,077	47,684
Net income (loss)	66,645	53,576	167,289	140,915
Less: Net (loss) income attributable to noncontrolling interest	(204)	(99)	(1,921)	(3)
Net income (loss) attributable to WESCO International, Inc.	66,849	53,675	169,210	140,918
Comprehensive Income:
Foreign currency translation adjustment	20,486	51,148	(37,029)	96,097
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	0	0	0	252
Comprehensive income attributable to WESCO International, Inc.	87,335	104,823	132,181	237,267
Parent Company [Member]
Condensed Financial Information [Line Items]
Revenues	0	0	0	0
Cost of goods sold	0	0	0	0
Selling, general and administrative expense	0	0	0	0
Depreciation and amortization	0	0	0	0
Income (Loss) from Subsidiaries, before Tax	66,645	53,576	167,289	140,915
Other Nonoperating Income (Expense)	0	0	0	0
Provision for income taxes	0	0	0	0
Net income (loss)	66,645	53,576	167,289	140,915
Less: Net (loss) income attributable to noncontrolling interest	0	0	0	0
Net income (loss) attributable to WESCO International, Inc.	66,645	53,576	167,289	140,915
Comprehensive Income:
Foreign currency translation adjustment	20,486	51,148	(37,029)	96,097
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax				(252)
Comprehensive income attributable to WESCO International, Inc.	87,131	104,724	130,260	237,264
Non-Guarantor Subsidiaries [Member]
Condensed Financial Information [Line Items]
Revenues	1,206,174	1,169,377	3,578,653	3,289,693
Cost of goods sold	981,908	954,109	2,915,387	2,675,608
Selling, general and administrative expense	134,683	139,859	420,353	405,029
Depreciation and amortization	11,143	11,599	33,572	33,947
Income (Loss) from Subsidiaries, before Tax	0	0	0	0
Other Nonoperating Income (Expense)	3,923	(8,601)	13,372	(25,492)
Provision for income taxes	12,746	18,499	37,876	50,718
Net income (loss)	61,771	53,912	158,093	149,883
Less: Net (loss) income attributable to noncontrolling interest	(204)	(99)	(1,921)	(3)
Net income (loss) attributable to WESCO International, Inc.	61,975	54,011	160,014	149,886
Comprehensive Income:
Foreign currency translation adjustment	20,486	51,148	(37,029)	96,097
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax				(252)
Comprehensive income attributable to WESCO International, Inc.	82,461	105,159	122,985	246,235
Consolidated Entities [Member]
Condensed Financial Information [Line Items]
Revenues	2,067,245	2,000,159	6,165,154	5,682,375
Cost of goods sold	1,670,037	1,614,814	4,988,103	4,580,896
Selling, general and administrative expense	284,073	280,497	867,790	815,653
Depreciation and amortization	15,618	16,074	47,321	47,758
Income (Loss) from Subsidiaries, before Tax	0	0	0	0
Other Nonoperating Income (Expense)	(17,050)	(16,835)	(54,574)	(49,469)
Provision for income taxes	13,822	18,363	40,077	47,684
Net income (loss)	66,645	53,576	167,289	140,915
Less: Net (loss) income attributable to noncontrolling interest	(204)	(99)	(1,921)	(3)
Net income (loss) attributable to WESCO International, Inc.	66,849	53,675	169,210	140,918
Comprehensive Income:
Foreign currency translation adjustment	20,486	51,148	(37,029)	96,097
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax				(252)
Comprehensive income attributable to WESCO International, Inc.	87,335	104,823	132,181	237,267
Guarantor Subsidiaries [Member]
Condensed Financial Information [Line Items]
Revenues	899,994	867,973	2,703,468	2,490,102
Cost of goods sold	727,052	697,896	2,189,683	2,002,708
Selling, general and administrative expense	149,390	140,638	447,437	410,624
Depreciation and amortization	4,475	4,475	13,749	13,811
Income (Loss) from Subsidiaries, before Tax	61,771	42,726	158,093	117,907
Other Nonoperating Income (Expense)	(13,127)	(25,436)	(41,202)	(74,961)
Provision for income taxes	1,076	(136)	2,201	(3,034)
Net income (loss)	66,645	42,390	167,289	108,939
Less: Net (loss) income attributable to noncontrolling interest	0	0	0	0
Net income (loss) attributable to WESCO International, Inc.	66,645	42,390	167,289	108,939
Comprehensive Income:
Foreign currency translation adjustment	20,486	51,148	(37,029)	96,097
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax				(252)
Comprehensive income attributable to WESCO International, Inc.	87,131	93,538	130,260	205,288
Consolidation, Eliminations [Member]
Condensed Financial Information [Line Items]
Revenues	(38,923)	(37,191)	(116,967)	(97,420)
Cost of goods sold	(38,923)	(37,191)	(116,967)	(97,420)
Selling, general and administrative expense	0	0	0	0
Depreciation and amortization	0	0	0	0
Income (Loss) from Subsidiaries, before Tax	(128,416)	(96,302)	(325,382)	(258,822)
Other Nonoperating Income (Expense)	0	0	0	0
Provision for income taxes	0	0	0	0
Net income (loss)	(128,416)	(96,302)	(325,382)	(258,822)
Less: Net (loss) income attributable to noncontrolling interest	0	0	0	0
Net income (loss) attributable to WESCO International, Inc.	(128,416)	(96,302)	(325,382)	(258,822)
Comprehensive Income:
Foreign currency translation adjustment	(40,972)	(102,296)	74,058	(192,194)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax				504
Comprehensive income attributable to WESCO International, Inc.	(169,388)	(198,598)	(251,324)	(451,520)
Pension Plan [Member]
Condensed Financial Information [Line Items]
Other Nonoperating Gains (Losses)	$ (500)	$ (500)	$ (1,400)	$ (1,400)

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CONDENSED CONSOLIDATED STATEMENT OF CASH FLOWS (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Condensed Financial Information [Line Items]
Payments for (Proceeds from) Other Investing Activities	$ 3,609	$ 3,490
Net cash (used) provided by operating activities	174,460	81,111
Investing Activities:
Capital expenditures	(23,749)	(15,970)
Net cash used in investing activities	(20,140)	(12,480)
Financing Activities:
Payments for Repurchase of Common Stock	(27,055)	(106,702)
Proceeds from (Payments for) Other Financing Activities	(8,301)	(4,380)
Net cash used in financing activities	(124,820)	(92,164)
Effect of exchange rate changes on cash and cash equivalents	(4,693)	7,485
Net change in cash and cash equivalents	24,807	(16,048)
Cash and cash equivalents at the beginning of period	117,953	110,131
Cash and cash equivalents at the end of period	142,760	94,083
Parent Company [Member]
Condensed Financial Information [Line Items]
Payments for (Proceeds from) Other Investing Activities	0	0
Net cash (used) provided by operating activities	14,198	(28,740)
Investing Activities:
Capital expenditures	0	0
Proceeds from Dividends Received	0	0
Net cash used in investing activities	0	0
Financing Activities:
Borrowings	12,857	135,442
Repayments	0	0
SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Subsidiaries and Equity Method Investees	0	0
Payments for Repurchase of Common Stock	(27,055)	106,702
Proceeds from (Payments for) Other Financing Activities	0	0
Net cash used in financing activities	(14,198)	28,740
Effect of exchange rate changes on cash and cash equivalents	0	0
Net change in cash and cash equivalents	0	0
Cash and cash equivalents at the beginning of period	0	0
Cash and cash equivalents at the end of period	0	0
Guarantor Subsidiaries [Member]
Condensed Financial Information [Line Items]
Payments for (Proceeds from) Other Investing Activities	(81,128)	(174,032)
Net cash (used) provided by operating activities	62,439	168,603
Investing Activities:
Capital expenditures	(12,831)	(7,435)
Proceeds from Dividends Received	118,271	51,561
Net cash used in investing activities	24,312	(129,906)
Financing Activities:
Borrowings	246,323	557,391
Repayments	(318,323)	(587,485)
SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Subsidiaries and Equity Method Investees	0	0
Payments for Repurchase of Common Stock		0
Payments for Repurchase of Private Placement	0
Proceeds from (Payments for) Other Financing Activities	(8,301)	(4,380)
Net cash used in financing activities	(80,301)	(34,474)
Effect of exchange rate changes on cash and cash equivalents	0	0
Net change in cash and cash equivalents	6,450	4,223
Cash and cash equivalents at the beginning of period	50,602	41,552
Cash and cash equivalents at the end of period	57,052	45,775
Non-Guarantor Subsidiaries [Member]
Condensed Financial Information [Line Items]
Payments for (Proceeds from) Other Investing Activities	3,609	16,711
Net cash (used) provided by operating activities	97,823	(58,752)
Investing Activities:
Capital expenditures	(10,918)	(8,535)
Proceeds from Dividends Received	0	0
Net cash used in investing activities	(7,309)	8,176
Financing Activities:
Borrowings	933,046	691,682
Repayments	(882,239)	(617,301)
SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Subsidiaries and Equity Method Investees	(118,271)	(51,561)
Payments for Repurchase of Common Stock	0	0
Proceeds from (Payments for) Other Financing Activities	0	0
Net cash used in financing activities	(67,464)	22,820
Effect of exchange rate changes on cash and cash equivalents	(4,693)	7,485
Net change in cash and cash equivalents	18,357	(20,271)
Cash and cash equivalents at the beginning of period	67,351	68,579
Cash and cash equivalents at the end of period	85,708	48,308
Consolidated Entities [Member]
Condensed Financial Information [Line Items]
Payments for (Proceeds from) Other Investing Activities	3,609	3,490
Net cash (used) provided by operating activities	174,460	81,111
Investing Activities:
Capital expenditures	(23,749)	(15,970)
Proceeds from Dividends Received	0	0
Net cash used in investing activities	(20,140)	(12,480)
Financing Activities:
Borrowings	1,111,098	1,210,608
Repayments	(1,200,562)	(1,191,690)
SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Subsidiaries and Equity Method Investees	0	0
Payments for Repurchase of Common Stock	27,055	106,702
Proceeds from (Payments for) Other Financing Activities	(8,301)	(4,380)
Net cash used in financing activities	(124,820)	(92,164)
Effect of exchange rate changes on cash and cash equivalents	(4,693)	7,485
Net change in cash and cash equivalents	24,807	(16,048)
Cash and cash equivalents at the beginning of period	117,953	110,131
Cash and cash equivalents at the end of period	142,760	94,083
Consolidation, Eliminations [Member]
Condensed Financial Information [Line Items]
Payments for (Proceeds from) Other Investing Activities	81,128	160,811
Net cash (used) provided by operating activities	0	0
Investing Activities:
Capital expenditures	0	0
Proceeds from Dividends Received	(118,271)	(51,561)
Net cash used in investing activities	(37,143)	109,250
Financing Activities:
Borrowings	(81,128)	(173,907)
Repayments	0	(13,096)
SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Subsidiaries and Equity Method Investees	(118,271)	(51,561)
Payments for Repurchase of Common Stock	0	0
Proceeds from (Payments for) Other Financing Activities	0	0
Net cash used in financing activities	37,143	(109,250)
Effect of exchange rate changes on cash and cash equivalents	0	0
Net change in cash and cash equivalents	0	0
Cash and cash equivalents at the beginning of period	0	0
Cash and cash equivalents at the end of period	$ 0	$ 0

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GOODWILL (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Goodwill [Line Items]
Goodwill	$ 1,755,292	$ 1,771,877
Goodwill, Foreign Currency Translation Gain (Loss)	$ (16,585)

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REVENUE (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Deferred Revenue	$ 8,800		$ 8,800		$ 15,500
Revenue from Contract with Customer, Excluding Assessed Tax	2,067,245	$ 2,000,159	6,165,154	$ 5,682,375
Cost of goods sold	1,670,037	1,614,814	4,988,103	4,580,896
Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	723,869	722,227	2,243,590	2,111,813
Construction [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	686,165	674,996	2,007,708	1,870,406
Utility [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	345,937	312,501	998,438	861,162
Commercial, Institutional and Government [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	311,274	290,435	915,418	838,994
UNITED STATES
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,525,393	1,473,016	4,571,533	4,267,684
Non-US [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	541,852	527,143	1,593,621	1,414,691
Shipping and Handling [Member]
Disaggregation of Revenue [Line Items]
Cost of goods sold	$ 18,800	$ 15,500	$ 55,600	$ 43,200

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REVENUE Deferred Revenue (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Deferred Revenue	$ 8.8	$ 15.5

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REVENUE Shipping and Handling Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Cost of goods sold	$ 1,670,037	$ 1,614,814	$ 4,988,103	$ 4,580,896
Shipping and Handling [Member]
Cost of goods sold	$ 18,800	$ 15,500	$ 55,600	$ 43,200

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REVENUE Variable Consideration (Details)

9 Months Ended

Sep. 30, 2018

Revenue from Contract with Customer [Abstract]

Revenue Recognition, Revenue Reductions [Policy Text Block]

WESCO’s revenues are adjusted for variable consideration, which includes customer volume rebates, returns, and discounts. WESCO measures variable consideration by estimating expected outcomes using analysis and inputs based upon anticipated performance, historical data, as well as current and forecasted information. Measurement and recognition of variable consideration is reviewed by management on a monthly basis and revenue is adjusted accordingly. Variable consideration reduced revenue for the three months ended September 30, 2018 and 2017 by approximately $25.1 million and $24.2 million, respectively, and by approximately $74.5 million and $66.5 million for the nine months ended September 30, 2018 and 2017, respectively.

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REVENUE Revenue, Performance Obligation (Details)	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue, Performance Obligation, Description of Timing	WESCO’s revenue arrangements generally consist of single performance obligations to transfer a promised good or service, or a combination of goods and services. Revenue is recognized when control has transferred to the customer, which is generally when the product has shipped from a WESCO facility or directly from a supplier. For products that ship directly from suppliers to customers, WESCO acts as the principal in the transaction and recognizes revenue on a gross basis. Revenue for integrated supply services is recognized over time based on hours incurred. This method reflects the transfer of control as the customer benefits from these services as they are being performed. WESCO generally satisfies its performance obligations within a year or less.
Revenue, Performance Obligation, Description of Payment Terms	payments are normally received within 60 days
Revenue, Performance Obligation, Description of Warranty	WESCO generally passes through the warranties offered by the applicable manufacturer or supplier to its customers.

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NET INTEREST AND OTHER (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018
Other Income and Expenses [Abstract]
Foreign Currency Transaction Gain (Loss), before Tax	$ 0.1	$ 2.6